To clear things up, I’ve put together a basic Twitter guide that explains how to use it, Twitter lingo, privacy options, mobile applications that can be used with the service and problems that it has. Let’s get started.

Twitter limits social-networking updates to 140 characters or less. The service is surprisingly useful, but leaves room for improvement.

What is it? In short, Twitter is a free social-networking tool that keeps people connected with one another and with sources of information. Twitter users submit updates about whatever they’re currently doing, and these updates cannot exceed 140 text-based characters.

Lingo: Twitter is the name of the service. The term twittering describes the activity of updating a Twitter account. A tweet is an individual Twitter update. Twitterers are people who use the service.

Followers, not Friends: Social-networking sites like Facebook and MySpace use the term “friend” to refer to people who are connected with one another, but Twitterers can simply follow one another’s messages by finding a person’s username and selecting a “Follow” option. This alerts the person that you’re following them, and they can reciprocally choose to follow you, or not.

Why use it? While some people primarily use Twitter to post updates about their activities or comments on the news, I use the service more as a follower, allowing me to see quick snippets of news as it occurs. Most tweets are written by real people, while others, such as updates from news organizations that you’ve selected, are automatically generated. Many tweets include the addresses of Web sites with relevant articles that tell readers more on a topic.

Where is it? Twitter works on your Web browser at Twitter.com, where user updates appear in a simple list form as they are submitted. After you’ve signed up and started following other people, those people’s updates, or tweets, will appear when you log onto Twitter.com using a username and password.

Twitter also works on mobile phones, where the 140-character limit allows messages to be sent and received via SMS text messaging. Tweets can also be sent and received via email. Users with smartphones like BlackBerrys or iPhones can use one of the many popular mobile applications for accessing Twitter, which offer much richer options than simple SMS does; I’ll get into these later.

Privacy: Unlike other social-networking sites such as Facebook, Twitter isn’t focused on holding and sharing personal information about its members. Indeed, the service operates with a majority (80%, according to the company) of users opting to keep their updates public, that is, follow-able by anyone, without permission. This openness encourages people to follow one another or to see who others are already following, and then follow the same people.

However, users can opt to protect their updates, meaning they must grant permission for others to follow them. If you’d like to sign up for Twitter, but aren’t comfortable putting your first and/or last name on the site, you don’t have to; instead, just tell others your username.

Twitter Page Personalization: Each user has a Twitter page showing all of his or her updates, or tweets. (Mine is twitter.com/kabster728, and you can follow me.) This page also shows the number of people a user follows, how many people follow her and how many total updates she has posted.

Twitterers can customize their Twitter page by uploading a photo to be used as the background. The icon representing each user can also be personalized, and this is important because it appears beside that person’s tweets on Twitter.com, where followers recognize and appreciate its familiarity. Some people, including me, use pictures of themselves as their icons, while others use random shots.

Apps/Clients: Twitter works on any browser, and will also work on a mobile browser. If you have a mobile device like the BlackBerry or iPhone, you can jazz up the experience by downloading a third-party app like TwitterFon, TwitterBerry, Tweetie or Twitteriffic. Twittervision, another mobile app, plots points on maps to show where tweets originated. Desktop clients also abound, including Twhirl and TweetDeck. Twitterfeed will set your blog to automatically post content to Twitter.

@Replies, Direct Messages: Each tweet that appears in your Twitter feed can be replied to using a shortcut arrow that appears beside the tweet, and these responses to tweets are called @Replies. So if JoeSchmo tweets to say he saw the new James Bond movie and hated it, you can reply to this with a tweet of your own that says, “@JoeSchmo I still adore Daniel Craig.” These @Replies appear for everyone to see, and must start with @ plus the username of whomever you’re responding to.

Direct Messages differ from @Replies because they can be sent only between people who are following one another. These messages aren’t posted publicly. They appear on your Twitter.com page in a right-side section labeled Direct Messages and will also be sent to your mobile device if you have one registered with Twitter.

Favorites: If you read a tweet that you really like, you can save it as a favorite by selecting a small star beside the tweet, thus adding it to a Favorites section on your homepage. Anyone can see anyone else’s Favorites, regardless of whether or not they’re following one another.

Problems: Twitter’s bare-bones approach gets to the point quickly, displaying tweets in a simple, quick-read format. But the site is lacking in many areas. It used to enable searching for people on Twitter, but that capability is currently down. Now, to search for friends on Twitter, you must upload your email contacts from a Web-based mail service. The company says it plans to have people-search working again by the end of the year. Meanwhile, search.twitter.com enables keyword or location searches.

Twitter lacks the ability to sort tweets according to what the user wants. If I just want to see tweets from real people and not those that are automatically generated, I’m out of luck. Same goes if I want to keep certain friends’ tweets in a prominent place on my homepage; Twitter has no way of doing this.

Twitter users aren’t notified when someone responds to their tweet with an @Reply. I recently happened to look at @Replies on my Twitter homepage and found three from people who follow me (I don’t follow them).

If you’re adding a Web address to a tweet and the characters in the URL take up too much space, Twitter will automatically use TinyURL behind the scenes to shrink your long link into a shorter one when you post your tweet. But this works only if you have enough remaining characters in your tweet to fit the long version of your link. A built-in TinyURL converter on the page would help immensely.

Twitter says it’s working to make @Replies more effective. It also says it plans to do more with filtering and sorting, so that the Twitter interface is more useful. In the meantime, Twitter does a good job of giving people simplified news about others and the world around them. If you’re often in a rush, Twitter can be a great resource for fast information.

Edited by Walter S. Mossberg

• Email us at mossbergsolution@wsj.com. Find this and other columns and videos online free at the All Things Digital Web site: http://walt.allthingsd.com

AOL’s AIM started out with enough popularity to freely ignore the need to integrate with other programs; now, it can be argued that AIM retains its relevancy by operating with other messaging programs like Google’s Gmail chat and Apple’s iChat. Other IM clients paired up with one another to increase usability, like when Microsoft and Yahoo became interoperable over two years ago.

But nowadays, social-networking offerings — like leaving messages on Facebook walls and receiving Twitter “tweets” from friends — compete with traditional instant-messaging programs. And advanced technology in mobile devices has helped these chats move from desktops to iPhones and BlackBerrys, where conversations can continue on-the-go, using mobile applications.

Three free programs — Meebo, Adium and Digsby — work by consolidating numerous messaging accounts into one combined program.

This week I tested three free programs that seem to acknowledge the fading star of isolated instant messaging, as we once knew it. Meebo, Adium and Digsby work by consolidating numerous messaging accounts into one combined program. Some of these include social-networking integration or even built-in email notifications, turning the service into a one-stop shop for online communication. The result can save people from choosing one IM system over another.

All three of these programs are straightforward and work without much effort or instruction. They require users to enter the user names and passwords to log onto each IM account, which may make some people uncomfortable, even though each site explains its privacy policy. Of the three, Digsby offers to integrate with the greatest number of programs all at once, including instant messaging, email and social-networking accounts. It also lets people handle email by deleting or sorting it directly in the IM window, which neither of the other programs does.

But Digsby isn’t yet usable on Macs or Linux, and Adium (the second-best offering) is available only on Macs. When used with the correct operating system, these programs perform as promised, easing communication overall and saving people the hassle of logging into various accounts — or missing out on chats with friends because of not signing into certain programs.

Meebo, www.meebo.com, is the only one of these three products that is completely Web-based. It works on all major browsers, including Internet Explorer, Firefox and Safari, and doesn’t require any installation — a plus for those who would like to be using instant messaging in the office but aren’t able to install software on corporate computers. It can log users into one of six messaging programs simultaneously, including Yahoo, Microsoft, AIM, Google, ICQ and Jabber.

I signed onto three instant-messaging accounts at once on Meebo by entering the username and password for each and selecting one overall “Sign In” button, which logged me into each program simultaneously and displayed all of my contacts in one condensed panel. Meebo can be configured to automatically launch within Firefox if a Firefox extension is downloaded.

Meebo.com is also usable on the iPhone and iPod Touch, allowing people to log into multiple accounts simultaneously from their mobile device. As of now, neither Adium nor Digsby has an application that allows it to work with the iPhone or iPod Touch.

Digsby, www.digsby.com, was a cinch to set up on my laptop, which was running Windows Vista. It walked me through the steps of adding accounts from instant-messaging programs, email accounts such as Gmail and Hotmail, and social-networking sites such as Facebook, MySpace and Twitter. Digsby works with IM and emails accounts from AOL/AIM, Yahoo, Microsoft and Google. Jabber, ICQ and Facebook chats also work with Digsby, along with IMAP and POP email accounts.

Once added, all of these accounts are represented in one clean panel. These consolidated communication programs saved me many extra clicks on my computer over a weekend, and I easily chatted with friends while checking messages. New emails received in my Gmail account were visible in a preview panel that popped up when I moved my cursor over the email account name. Right within this email preview panel, I could delete or archive each message; I was also able to mark a message as read or report it as spam. I performed all of these email tasks without opening my Gmail account in a browser or email client. Shortcuts in this preview panel labeled Open, Compose and Inbox sent me to my browser to perform these more-involved tasks.

This in-line functionality also applies to other email accounts, according to Digsby. But though I could see a tally of newly received Hotmail messages in my Digsby preview panel, these messages weren’t as interactive as those received in my Gmail inbox.

Digsby also tracks Twitter alerts and timelines, as well as Facebook newsfeeds and alerts — including posting notifications in your Digsby panel whenever someone “friends” you on Facebook.

Adium, www.adiumx.com, wins points for cuteness. The downloaded program is represented by a goofy, green duck, which plops itself in the Mac operating system dock and closes its eyes when not in use. When new messages are received via Adium, this duck flaps its wings until you open the message. The Adium user interface incorporates sleek visuals, such as status windows that gracefully float above user names whenever a cursor moves over these names.

Adium works with AIM, ICQ, .Mac, Jabber, Google Talk, Windows Live Messenger and Yahoo Messenger. Adium supports new email notifications for some accounts, but doesn’t enable reading or sending email within the program. Instead, it offered to open my account via the browser or using Microsoft Entourage on the Mac. Social networking is limited to MySpace IM on Adium, though the next version will support Facebook Chat.

Adium organizes multiple conversations using tabs stacked at the bottom of a chat window. Icons line the top of each chat window, such as a file icon for transferring files and a lock that switches a conversation to be encrypted and off-the-record. Any conversation that isn’t designated encrypted is automatically stored in a table of Adium transcripts, which can be sorted by To, From or Date. Transcripts can be sorted using rough timelines like “within the past two weeks” or “since yesterday.”

I saved myself time and mouse clicks by using these three consolidation programs, though I preferred Digsby in the end because of its intuitive email integration. These programs will help to take down the instant-messaging barriers that have become turn-offs over the past couple years, and may better integrate IM with the social networks and mobile devices that are on the rise.

Edited by Walter S. Mossberg

Write to the Mossberg Solution at mossbergsolution@wsj.com

This week, I tested two free Web sites that don’t try to steal users away from their trusted travel Web sites. Instead, these sites attempt to make your already booked reservations more useful and accessible.

I tested two such sites: TripIt Inc.’s www.TripIt.com, which acts as a virtual assistant to generate schedules using your reservations; and Groopvine (http://Groopvine.Groople.com), a feature offered by Groople, Englewood, Colo., that brings social networking to group travel plans. Both travel aids became available in September, though Groopvine has been released only in its beta, or testing, stage.

As someone who makes travel arrangements for about 10 work-related or personal trips every month, I paid close attention to the simplicity and usefulness of these sites. TripIt’s straightforward approach makes it addictive: When I forwarded travel confirmation emails to plans@tripit.com, the information in each reservation was automatically assessed, compiled and organized into a schedule, which was emailed to me in seconds.

Groople (a mashing of the words “Groups” and “People”) started four years ago as a site that helped big groups book hotels, flights and other travel arrangements. Groople’s new Groopvine tool offers group booking, but it focuses on working as an online forum where trips can be discussed among those in the traveling group. Photos, polls, videos and Web feeds can be added to each group’s trip page, prompting everyone to participate in the trip planning — or at least get excited about it.

I found a few hiccups on both sites. TripIt duplicates plans on a schedule if you accidentally forward a confirmation email more than once, and it works with most but not all reservations. Groopvine’s trip pages are rough around the edges in some places, obscuring key features and making certain flight and hotel ideas impossible to share with the group. But each site is helpful in its own way.

TripIt is a refreshing switch from the Web sites that force people to create usernames and passwords before doing anything. I started using TripIt by forwarding an Expedia email reservation to plans@tripit.com. Less than a minute later, I received an email from TripIt that included a link to my itinerary of flights, local weather forecasts for the duration of my vacation and maps related to where I was going. This email also included an assigned account ID (the email address from which I forwarded the reservation) and a password that I easily changed from within the account’s Web settings.

Along with this first test from Expedia, I forwarded a variety of other reservations to TripIt including bookings for a hotel in Atlanta, a rental car in Washington, D.C., and a round-trip Amtrak train from D.C. to Wilmington. I forwarded the reservations from various email addresses (as long as they were listed in my account), and each reservation was added to the right itinerary according to date.

TripIt can also accept forwarded restaurant reservations made on OpenTable or TopTable and will sort these into the itinerary.

This Web site’s idea of asking users to do very little to get a fully organized schedule works well, though everything can be edited. I unknowingly forwarded the same car rental to plans@tripit.com twice and two car reservations appeared on my itinerary, making me think I booked two cars until I saw the confirmation number repeated and deleted one. Attractive pre-loaded icons or your own photos can be added to the top of each schedule, as well as other plans for while you’re traveling, including images and Web links.

A feature called TripIt To Me lets you retrieve anything loaded into TripIt by simply emailing a command to the site, such as “Get Flight Tomorrow.” This worked well on my BlackBerry.

I started using Groopvine by signing up and creating a trip page for an annual vacation. I walked through steps to create my page, which I titled and set to a certain color scheme. I chose pink hues and added various sections to my page for displaying polls (to get votes from invited travelers), photos, videos, RSS feeds (for news related to the trip destination, for instance), weather, group discussions and useful Web sites.

I invited a group of friends to join my trip, and everyone accessed the trip page without needing to first become a member of Groopvine. Instead, usernames and passwords are automatically created for return sign-ins. In a few short steps, I made one poll asking friends where they thought we should go and another to ask them how many days they preferred to spend on vacation.

My fellow travelers and I added photos to the page that showed up in handsome Web 2.0 fashion, popping out from the screen in a box overlaid on the page at the click of a button. But I was disappointed that more of the site didn’t take advantage of this technology, which saves users from jumping to new Web pages. While browsing hotels and flights — two important parts of travel arrangements — I was directed to sites away from my personalized trip page.

Users can share hotel suggestions with the group by selecting up to five at once and asking others which they prefer, including details like room rates and amenities. When starting a trip, you must choose from a list to tell Groopvine what the trip is for (i.e. class reunion, sports team travel, family vacations, etc.). From that information, Groopvine suggests certain hotels depending on your group. A school trip, for example, would automatically return results with hotels rather than motels because motels don’t keep kids as contained and safe.

But in a search for Arizona hotels, I couldn’t share any of my choices with the group without first booking rooms. Groople says 70% of its hotels are shareable before booking, so I guess I picked the wrong city. I looked at flights and fares from various airlines, but (again) couldn’t share my findings with the group unless I booked a trip first or knew specific details about flight options. Groople says sharing flight information before booking — as is done with hotels — isn’t possible yet, though the company is working on finding a way to do it.

I’d prefer to share flight options with my group as I came across them. But it’s understandable that flights are difficult to share because fares change so often and various seats and fares are offered to members with different airline statuses. Another challenge with airlines is that only six reservations can be booked online at a time. Groople Agents, reachable by phone, can assist with challenges like these at no charge.

On March 11, Groople plans improvements for Groopvine, including fixing the hotels so that all of them are searchable and sharable. A new opt-in feature will automatically notify each traveler via email of changes on the trip site.

If you wish you had a personal assistant to arrange your travel reservations into a neat itinerary, TripIt does a great job and requires minimal effort and time. Its itineraries look polished, combining reservations into one neat list per trip that can be retrieved at any time. Groople’s Groopvine will encourage groups to get excited about their coming trip, whether they booked it through another favorite travel Web site or through Groopvine, itself. Hopefully, the impending fixes due in March will make this site’s pages more user-friendly.

• Email mossbergsolution@wsj.com.

On a chilly day, most folks find it tough to open the front door to retrieve the newspaper — much less climb a 15,000-foot mountain. But plenty of people court danger by rappelling down canyons and camping in remote woodlands. This week, I tested a device that will give thrill seekers a little extra insurance: It lets the folks back home track their progress, and learn when they’re OK or when they’re in trouble.

When activated, the $170 SPOT Satellite Messenger from SPOT Inc., the Milpitas, Calif., unit of Globalstar Inc., emits a signal to GPS satellites, which notify SPOT’s messaging service. The service then sends a message to friends, family or emergency rescue teams about your current status. Because it uses GPS technology, the SPOT will work even when you’re far from cellphone signal range and anywhere in the world.

I tested SPOT in my Washington, D.C., neighborhood (city parks still count as outdoorsy) and on a trip across the California desert and mountains on the way to a conference — though I was scaling mountains in an air-conditioned SUV rather than in a rock-climbing harness.

In my tests, SPOT worked without a problem. Notifications from the device were delivered to my friends via email and text message and included my current latitude and longitude. The service also sent along canned messages that I set up in advance on the company’s Web site at www.findmespot.com and hyperlinks to Google Maps that showed my location.

SPOT charges a $100 annual service fee, which includes an unlimited number of messages that can be sent out from your device using three buttons: OK/Check, Help and 911. An additional $50 per year tracking service called SPOTcasting follows and marks your exact location every 10 minutes for 24 hours each time it’s initiated.

This simple and straightforward device could really help in a dangerous situation. And the company takes its job seriously: A steely message on the SPOT packaging reads, “Opening this box is the first step in making sure you don’t come home in one.” But SPOT could also save the day in less-adventurous situations, such as when your car dies and you’re out of cellphone range.

However, SPOT isn’t perfect. While its three message-sending buttons make it easy to use, they also limit the types of messages it can send. There’s no keyboard, so messages must be brief and set up in advance on the Web site. And the device only sends messages and can’t receive them. Your friends and family have no way of getting back in touch with you on SPOT should you send a Help message from beyond cellphone range.

SPOT is a bright orange device with roughly the same surface measurement as a BlackBerry, though it’s considerably thicker. Its durable casing makes it waterproof and floatable, along with working in extremes like -40 degrees Fahrenheit and up to 21,000 feet above sea level. It runs on two AA lithium batteries, which last for different amounts of time according to the type of message being sent.

Setting up SPOT took only a few minutes on the Web site. A default or personalized message can be set up to go out with OK/Check and Help notifications, and email addresses and cellphone numbers (for SMS text messages) can be entered online as the destinations for these messages. Every message includes the user’s current location in terms of latitude and longitude, along with a hyperlink to access that location via Google Maps.

SPOT sends messages and location information via satellite, including points that can be tracked on a map.

The OK/Check button can be used most casually by owners of this gadget, as it merely serves to assure others that you’re fine. A good example might be two people on a three-month sailing trip who use this button as a means of checking in with family every Sunday night.

If OK/Check is held down for five seconds, it initiates the SPOTcasting tracking service (provided you’ve signed up for it) and locates your device every 10 minutes for a 24-hour period. These tracked points show up on SPOT’s Web site and are displayed as numbered points on Google Maps.

SPOT worked for me while driving through a regional park with a campsite, where cellphone range was faint, and up into boulder-crusted mountains. Just minutes after pressing Help or OK/Check or initiating tracking, friends received word of my location via emails and text messages.

You can’t set SPOT to track a trip for longer than 24 hours or at different intervals, such as every hour for a week. And the only way for others to view your tracked points is if they sign in using your online account’s username and password.

The Help button is used in more urgent situations and uses messages such as “Urgent help needed. Pick me up at campsite.” (The default for Help is “This is a HELP message. Please send for help ASAP.”) But preset messages shouldn’t be made too specific during the online setup because they can’t be changed from the device later.

The 911 and Help automatic notifications will always override less urgent messages like OK/Check or SPOTcasting. In the case of the 911 and Help buttons, one can be pressed after the other and the messages for both will still go out at the same time. The 911 button will send a message every five minutes until power runs out (the company says this will last for up to seven days) or until the message is canceled; Help sends a message every five minutes for an hour or until canceled.

The 911 button is more serious. When pressed, SPOT Inc. automatically notifies a certified 911 company called the GEOS International Emergency Response Center, which contacts your specified emergency contacts first to see if they know anything about your situation before dispatching a rescue squad using your coordinates.

If you can adjust to SPOT’s three-button approach, the device could be helpful for you or someone you know during outdoor adventures. Many people will buy SPOT simply for its 911 button, as an insurance policy on fluky cellphone service.

• Email mossbergsolution@wsj.com

Corrections & Amplifications:

The SPOT Satellite Messenger uses a global positioning system to determine a user’s location and a second satellite network to send notifications to friends, family and emergency services. This column erroneously stated that GPS satellites send notifications.