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

The Kodak Theatre HD Player’s motion-sensing pointer remote works much like a mouse on a TV screen.

This week I tested the Kodak Theatre HD Player, the photo-centric company’s attempt to snag valuable real estate in the living room. This small, black box pulls photos and videos from computers around the house and displays them on an HDTV. It also enables the sending and receiving of photos via Kodak Gallery, and connects to Web-based photos stored on Flickr, Facebook, Picasa, .Mac and others. Podcasts, Internet Radio and updates from news feeds, weather forecasts and stock quotes are also accessible using the HD Player. And it has a terrifically simple motion-sensing remote that works like using a mouse on a TV screen.

But the HD Player isn’t all smiles. Its $299 price doesn’t include any built-in storage for keeping content directly on the device. It currently has no way of accessing HD movies or television shows, nor will it work with Macs. In comparison, Apple’s (AAPL) $229 Apple TV has 40 gigabytes of storage, can access HD television shows and movies via the iTunes Store, and works with Macs and Windows PCs. This is important because as budgets tighten in the current economy, gadgets have to prove their value and versatility more than ever.

After using the Kodak Theatre HD Player with Windows XP and Vista machines over the past week, I can conclude that this device’s interface shines in its simplicity and is a lot of fun to use. Kodak teamed with Hillcrest Labs to make the player’s motion-sensitive remote and corresponding software, which includes satisfying extra features like images that automatically magnify when the remote control’s cursor points at them and icons that make chirping sounds when selected. The remote itself is shaped to rest comfortably in a hand and has three simple buttons and a scroll wheel.

Quick-access memory-card slots for six types of memory cards appear on the box’s front, and two USB ports can connect to digital cameras or USB storage devices.

Currently, the player’s software works directly with Flickr, RadioTime (8,750 radio stations) and FrameChannel, which grants access to various “channels” like Facebook, .Mac, Picasa, People.com news and National Geographic. Kodak says it will incorporate YouTube access in January; I got a sneak peek at the interface for this and it looks well-organized.

Yet the HD Player’s smart combination of software and remote left me wishing it did a bit more. Photo sharing is enabled only via Kodak Gallery, so you can’t use another Web-based account to share photos directly from your TV. Likewise, a blue light on the box slowly blinks only when new Picture Mail (a message containing shared photos) is received on a Kodak Gallery account, not when new photos are added on other sources such as Flickr Photostreams or Facebook pages.

The Home screen of the HD Player shows four categories: Pictures & Videos, Kodak Gallery, Music and Entertainment. Subcategories are where you might guess they would be, for example podcasts are listed under Entertainment. And a tiny Home icon appears in the top right corner of every screen so you can always get Home with one click. The Pictures & Videos category holds photos and videos from a currently selected Windows PC.

An unlimited number of Windows PCs can wirelessly pair with the player as long as they have special Kodak software installed on them. But only one PC’s content can be accessed at a time. I toggled between two paired computers without a problem, but would’ve preferred accessing music and photos from both sources simultaneously.

The HD Player’s motion-sensing pointer remote works much like a Wii remote control. Wherever you move it, a tiny leaf-shaped cursor appears on-screen. A Hide button on the remote will hide the cursor while you watch slideshows. The remote’s Back button is helpful; when pressed, it backs you out of one screen using visual effects that make the screen shrink into the TV as if you were moving backward.

A play button appears on the first photo in a folder so users can select this icon to quickly start slideshows. Whenever the HD Player receives new Kodak Gallery Picture Mail, or a slideshow is created on a connected PC, yellow alert circles appear on the screen to notify users and a number in the middle of these yellow circles indicates how many new items are available for viewing.

Some content on my PCs took a little while to be recognized by the HD Player, including podcasts that I subscribe to on iTunes. When they did show up, both audio and video podcasts played without issue and on-screen playback buttons made them easy to control.

The HD Player uses your photos to create automatically generated slideshows, called Picture Chronicles, once a week. These Picture Chronicles use up to 50 photos from the same time of year in all of your folders, for instance grouping all Thanksgiving photos together from the past five years.

Kodak has plans to make its player Mac-compatible in the future and also hopes to add other partnerships with new types of content following its YouTube announcement early next year.

The Kodak Theatre HD Player does its job well, bringing photos and videos that might otherwise live only on your PC to your big screen HDTV. For the holidays, this device could be a real plus. But Kodak has some work to do to make this a more useful Web-connected tool.

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