EDITORIAL NOTE: Virginia DeBolt (bio) writes the bi-weekly Elder Geek column for Time Goes By in which she takes the mystery out of techie things all bloggers and internet users need to know to simplify computer use. She has written several books on technology and keeps two blogs herself, Web Teacher and First 50 Words.

Twitter bears a resemblance to instant messaging and email, but it is also quite different. They've begun talking about Twitter on the evening news, so I guess it's gone mainstream. Here's a little primer on what it's all about.

The Basic Facts
Twitter is a communication tool. You are restricted to only 140 characters per Tweet (messages are called Tweets). Anyone can read your tweets, which is very different from email and instant messaging.

There is a way to communicate one-on-one with Twitter, but most tweets are sent out to the whole world. Normally, however, you don't want to read Tweets from everyone in the whole world.

You select who you will read, or "follow" on Twitter. You follow people you know or who share your interests, or whose daily lives matter to you. To follow someone, you find them on Twitter. To find me on Twitter, go to http://twitter.com/vdebolt and click the button that says "Follow." Every person who signs up with Twitter has a URL like mine, where you can see who they are and decide whether to follow them. Ronni is http://twitter.com/ronni7.

Twitter can be used in a browser, or on your phone, or using small applications that you install on your desktop. Two popular desktop apps are Tweetdeck and Twhirl. This image is a half-size version of what I see on my desktop using Twhirl.

You can ignore Twitter or watch it, using browser, phone or desktop application. If someone sends a message they want you to see, that's called an "at" message. If you start a tweet with @vdebolt, I'll get alerted that you are talking to me. I'm under no obligation to reply. Everyone on Twitter can see this message. You can tweet someone with a "direct" message. If you start a tweet with d vdebolt, it will come directly to me and no one else will see it.

So, What's the Big Deal?
Essentially, Twitter is just another way to satisfy the human urge to communicate. To connect. To micro-blog. To keep up with a few good friends.

But Twitter has characteristics that make it different and useful in a number of ways. Sure, you can learn that you grandkid is home from school with a cold today, but you can go far beyond that. You can go to the world, the whole world.

One important fact I mentioned is that you can see anyone's Tweets. Normally, you don't. But sometimes something extraordinary happens or a large number of people are all sharing an event. When this comes up, a special tag called a hash tag is created. Anyone who Tweets about that topic includes the appropriate hash tag in their tweet and it can be searched for using the Twitter search or at Hashtags.org.

In recent memory, there was a hashtag used for all the Tweets about the plane that landed in the Hudson River. The news about the crash was on Twitter (along with photos) in seconds after the event, and throughout the rescue. Anyone who searched on the hashtag could follow what was happening. In situations like this, you can really see the value of being able to read everyone's tweets. Most of the time, you don't want to, but sometimes it becomes crucial.

I sometimes use and search for the Tweets using the hashtag #abq. I live in Albuquerque, and I like to see if anything is going on I want to know about. This is one way to find out.

Okay, so maybe you are not impressed with knowing things about Albuquerque. But what if it was about hurricane or a power outage in your town or a blizzard or a plane crash or a flyash spill up the river from your neighborhood? Would being able to search using hashtags make sense to you then?

You don't even have to be signed up with Twitter to follow things that are Tweeted with hashtags. Just go to Hashtags.org and see what's popular or search for a hashtag you're interested in.

It's the Support
Many businesses are on Twitter. They have names like @Dell or @TheHomeDepot. You can send them messages and actually get a response and conduct a conversation about your concerns. I now have a very close relationship with the local Comcast guy who is @comcastscott on Twitter. (That's http://www.twitter.com/comcastscott if you want to follow him.) He listens, he follows through, he makes sure I'm happy with Comcast.

No, It's the Tracking
You can watch Twitter for a mention of anything such as the name of a book you wrote, a topic you care about, a movie you are thinking about going to see and so forth. Browse the search results to read what others are saying about it. You don't need hashtags for this. Just search for a word or words. You might search for Slumdog Millionaire. Or like Scott, from Comcast, you might search for the word Comcast.

In fact, businesses who ignore what is being said about them on Twitter do so at their own peril these days. A fast, caring response to a complaint can ward off a firestorm.

Really, It's the Connection
Like blogging, Tweeting gives you connections. It gives you access to people you may never know in real life, but can enjoy greatly as internet friends. In my daily life I work at my computer, I may go visit a neighbor, my son and granddaughter may visit for dinner, I may go to Tai Chi class, maybe I have a book club meeting. How many people is that I see: 15? 20? How many people do you see a day in real life? But I can share a laugh, a bit of news, or an interesting photo or web link with people from everywhere through Twitter.

But Wait, There's More
I've written about Twitter in a number of other places. On BlogHer: The Audience is Tweeting and Twitter: Ad Infinitum. On Web Teacher: Twitter in Education.

If you'd like to watch Evan Williams, the creator of Twitter, talking about Twitter's growth and uses, here's a video: Talks Evan Williams: How Twitter's spectacular growth is being driven by unexpected uses.

[At The Elder Storytelling Place today, Brenton “Sandy” Dickson has some important things to say about Hope.]