Twitter is a microblogging service that lets you write up to 140 characters at a time, then posts them the twitter site. You can then set up the service to display only those people you’ve expressed interest in (by “following” them) or you can view the posts of Everyone (though this would get overwhelming quickly!).

You can also set the system to send messages that other people post directly to your cell phone as a text message. I do this a lot when I’m traveling.

The original idea was for people to keep up with what their friends and family were doing – “I’m at the airport, come pick me up.” or “Who wants to have lunch?”. But it’s expanded a lot since then, and there are probably thousands of pages all over the web devoted to different ways to use Twitter.

When I originally signed up, I didn’t see much benefit to it. Then, at a conference, one of the committees I was on used Twitter to arrange meetings, change rooms as needed, and make sure everyone was well-informed. I was hooked!

I now try to post a couple of times a day, and if you look at my profile you’ll see that I follow a lot of people in my field, and also a couple of really famous, big name people. For example, Obama was tweeting, and now the whitehouse has its own account.

Another cool thing is the search feature. You can search for any word you like to see who’s talking about that subject. For events that I attend, there is often a “hash-tag” set up so that it is easy to find related posts. For example, the STC annual conference will be using #stc09 so that all posts – whether referring to it as a conference, summit, or meeting – can be gathered in one place.

There’s lots more, but I’ve got a preview to attend!