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

One way to find the information you want is by setting up computer-generated alerts. These electronic notifications are relatively simple to use and offer a range of helpful services, from a virtual heads-up when your name is mentioned online to messages about a product’s price suddenly dropping.

For years, I’ve used Google Alerts as a way of keeping track of myself online. If my name is mentioned in a blog or if this column appears on the Web, such as on the site of a newspaper that syndicates it, a Google Alert sends me an email about it. Google Alerts can work for you to find a variety of things, such as telling you if a video of a favorite band popped up online or that a blogger posted something about last night’s episode of “Mad Men.”

In about a month, Google will begin delivering these alerts to users via feeds, as well as emails. Google (GOOG) certainly isn’t alone in the alerts arena, as Yahoo (YHOO), Microsoft (MSFT) and AOL (TWX) are also players. This week I tried two small companies that recently joined the mission to help users find the Web content using alerts.

Pinpointing Searches

I tried Alerts.com and Yotify.com, and found worthwhile features in both. While Google Alerts does a good job of finding search terms in news, blogs and videos, Alerts.com and Yotify use forms that are a cinch to fill out and let you pinpoint your searches.

Alerts.com offers to notify users via email, SMS text messages or even voice calls to a cellphone or landline. The site organizes your alerts on a personalized Web page and uses a desktop application called Elertz to tell you when an alert has generated results. I liked this site’s flexibility: It not only gave me different ways to receive notifications, but also enabled a variety of options for time-specific deliveries of alerts.

But Yotify has advantages of its own, including the ability to integrate with FriendFeed and Facebook so friends can offer their recommendations or opinions. It also lets users search for event tickets or items auctioned on eBay (EBAY). And a smart preview panel gives you an idea of the type of results your search will return before you submit the request for an alert.

Viewing Results

For now, Google Alerts and Yotify will send alert notifications only via email, though all three services will let you view your alert results online. All three are free, but SMS alerts sent to a cellphone via Alerts.com may not be, depending on your plan.

All in all, I found there were certain things each service was good at doing. For example, Alerts.com lets me know college football scores when I want them: only after the final score; at the end of each quarter and after the final score; or at the end of each quarter, after the final score and after each time a team scores points. Yotify gave me detailed options in a Craigslist search for furniture, including showing only listings with photos or just those that included the word “sofa” in a title; it will even hunt for a specific price range.

For the person who wants to spend minimal time creating basic alerts, Google Alerts will do the trick. These can be narrowed down to show results that fall into the News, Web, Blogs, Video or Groups categories, or you can perform more-blanketed searches using a Comprehensive category.

Alerts.com offers plenty of simple alerts that require only a bit of scheduling to set up. Each alert appears as a widget that can be expanded, edited or deleted with a simple click, and this page has a clean look with attractive, cohesive graphics.

I didn’t care much for Elertz, the desktop component of Alerts.com, because once installed, it notified me of new Alerts data using an irksome star that glowed red until I checked my notifications. Elertz didn’t work properly on my Windows XP machine until Alerts.com fixed a bug.

But Alerts.com’s price watch and price protection alerts are incredibly useful. Price watch looks to see if an item’s price drops into a lower price range, at which point users are notified. Price protection watches to see if products you bought are now on sale so you can get a refund. I tried both, and I’m hoping I’ll hear soon that a specific pair of Anthropologie boots is on sale.

Yotify uses the idea of virtual scouts that scour the Web for specific information. Scout findings can be condensed or expanded in one click, and results can be filtered for more specific findings or shared with friends via Facebook or FriendFeed.

Scout Work

But some scouts took too much work to set up. When I tried to set up a scout for college football scores, I didn’t see a sports category (Alerts.com had a colorful NCAA icon right on its home page). Instead, I had to choose News, then select ESPN, then NCAAF and finally enter “Penn State” in a key word box for my scout. And after all that, the scout offered results only daily or hourly via email.

I would also prefer if I could better organize my scout lists. As it was, all of my results appeared in one list: The NCAA scout was right above the scout that found Obama mentions on Huffington Post, and below that were results for YouTube’s most-watched videos. Yotify says it will add ways to more neatly arrange data in the next month or so.

On average, Yotify returned more results instantly, such as 10 instant Craigslist sofa results compared with Alerts.com’s two in the first few hours.

Overall, these sites are worth trying so you can find which alert system works best for you and stop wasting time searching the Web the old-fashioned way.

– 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