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

But the vastness of the Internet can leave many people wondering where to begin, especially when asking sensitive questions about education. And, even in a sea of discussions and forums on education, parents are often hungry for one piece of information above all else: data that helps them select a school for their children.

Education.com’s SchoolFinder (top right) enhances an already rich Web site (top left), while GreatSchools.net (above) works education-related content into school search results.

So this week I tried three education-related Web sites that dedicate some or all of their resources toward providing free school comparisons, including demographics, test results, teacher-to-student ratios and percentages of students eating free and reduced-price lunches.

I performed various school queries using Education.com Inc., GreatSchools Inc.’s GreatSchools.net and SchoolMatters.com by typing in a ZIP Code, city, district or school name. Overall, GreatSchools and Education.com offered the most content-packed environments, loading their sites with related articles and offering community feedback on education-related issues by way of blog posts or surveys. And though GreatSchools is 10 years older than Education.com, which made its debut in June, the latter has a broader variety of content and considers its SchoolFinder feature — newly available as of today — just a small part of the site.

Both Education.com and GreatSchools.net base a good portion of their data on information gathered by the Department of Education and the National Center for Education Statistics, the government entity that collects and analyzes data related to education.

SchoolMatters.com, a service of Standard & Poor’s, is more bare-bones, containing quick statistical comparisons of schools. (S&P is a unit of McGraw-Hill Cos. [MHP]) This site gets its content from various sources, including state departments of education, private research firms, the Census and National Public Education Finance Survey. This is evidenced by lists, charts and pie graphs that would make Ross Perot proud. I learned about where my alma mater high school got its district revenue in 2005: 83% was local, 15% was state and 2% was federal. But I couldn’t find district financial information for more recent years on the site.

All three sites base at least some school-evaluation results on test scores, a point that some of their users critique. Parents and teachers, alike, point out that testing doesn’t always paint an accurate picture of a school and can be skewed by various unacknowledged factors, such as the number of students with disabilities.

Education.com’s SchoolFinder feature is starting with roughly 47,000 schools in 10 states: California, Texas, New York, Florida, Illinois, Pennsylvania, Ohio, Michigan, New Jersey and Georgia. In about two months, the site hopes to have data for all states, totaling about 60,000 public and charter schools. I was granted early access to SchoolFinder, but only Michigan was totally finished during my testing.

SchoolFinder lets you narrow your results by type (public or charter), student-to-teacher ratio, school size or Adequate Yearly Progress (AYP), a measurement used to determine each school’s annual progress. Search results showed specific details on teachers that I didn’t see on the other sites, such as how many teachers were fully credentialed in a particular school and the average years of experience held by a school’s teachers.

The rest of the Education.com site contains over 4,000 articles written by well-known education sources like the New York University Child Study Center, Reading is Fundamental and the Autism Society of America. It also contains a Web magazine and a rather involved discussion-board community where members can ask questions of like-minded parents and the site’s experts, who respond with advice and suggestions of articles that might be helpful.

Private schools aren’t required to release test scores, student or teacher statistics, so none of the sites had as much data on private schools. However, GreatSchools.net at least offered basic results for most private-school queries that I performed, such as a search for Salesianum School in Delaware (where a friend of mine attended) that returned the school’s address, a list of the Advanced Placement exams it offered from 2006 to 2007 and six rave reviews from parents and former students.

GreatSchools.net makes it easy to compare schools, even without knowing specific names. After finding a school, I was able to easily compare that school with others in the geographic area or school district — using a chart with numerous results on one screen. After entering my email address, I saved schools to My School List for later reference.

I couldn’t find each school’s AYP listed on GreatSchools.net, though these data were on Education.com and SchoolMatters.com.

SchoolMatters.com doesn’t provide articles, online magazines or community forums. Instead, it spits out data — and lots of it. A search for “Philadelphia” returned 324 schools in a neat comparison chart that could, with one click, be sorted by grade level, reading test scores, math test scores or students per teacher. (The Julia R. Masterman Secondary School had the best reading and math test scores in Philadelphia, according to the site.)

SchoolMatters.com didn’t have nearly as much user feedback as Education.com or GreatSchools.net. But stats like a school’s student demographics, household income distribution and the district’s population age distribution were accessible thanks to colorful pie charts.

These three sites provide a good overall idea of what certain schools can offer, though GreatSchools.net seems to have the richest content in its school comparison section. Education.com excels as a general education site and will be a comfort to parents in search of reliable advice. Its newly added SchoolFinder, while it’s in early stages now, will only improve this resource for parents and students.

Edited by Walter S. Mossberg

Email mossbergsolution@wsj.com