By now most people have figured out what Twitter is - micro blogging of 140 characters or less. Many people can't figure out the point, though. Are you telling all your friends every time you get on the train or have another cup of coffee or something? While you can do this, and some people's Tweets (posts to Twitter) are inane and numerous, there is some gold.

Think of it like a pre frontal lobe blog crossed with a general IM. When something's going on you'd blog about if you had the time and motivation, you post. When you're doing something interesting or where you might want input, or if you feel like telling everyone what's going on without contacting people individually, you write something. Going to write an article? Post and get feedback and more info. Working on something? Post about it. Maybe it's been done already, or someone else would like to see what you're doing.

You can hook Twitter in and out of other sites and applications - make your Tweets update your Facebook status, make your blog updates go out to people following you on Twitter, etc. It's good to have some useful chatter on what you're doing. You don't have to post the same thing in a million places if they're all connected, and it's lets people know what you're up to, what your expertise is, where you could use help, what your interests are, etc.

There's a slight learning curve with Twitter. If you want to reply publicly to someone start with @name. The person you're responding to will see it, as well as anyone else who is following you. If you want to send a private message (direct), start with d name. This will only work if you're following each other. Only they will see the message.

This brings us to Follow. Before we get deep into that, it's important to get an idea of where you monitor things. You can see updates via the Twitter website, where you can also see replies and users names are links to their Twitter pages, which is useful. You can also use Twitter via a large number of applications, via IM and SMS. And you can specify whether you want to receive updates from each user you're following. To the best of my knowledge there's no way to turn them all on or off. You have to do it individually. You may want to follow some chatty people but don't want to see their every update via IM or SMS (some people post a lot. Think constantly).

Another surprising missing feature is to search and add people to follow from an export of your address book. If you use Gmail or various other web based emails you're OK, though.

While you can watch the public stream of Twitter updates (https://twitter.com/public_timeline [1]) there's also a way to narrow this down, though strangely it's only via IM or SMS. Connect your IM to Twitter on the Twitter site, then write Track term to get all public tweets containing that term. This is an awesome way to network and learn. I've gotten leads and hired people I've found through track on Twitter.  There are sites that help you see all posts on a term and let you track them via RSS, which can be less overwhelming than getting 200 messages a day that happen to contain a certain term. BTW, there's no taxonomy, so the term must appear in the message posted. No threading, either, and if you track something like QA all posts containing something like Al Qaida will get to you, too.

Check out my del.icio.us bookmarks on Twitter to find some really useful tools and thoughts on Twitter: http://del.icio.us/joshmccormack/twitter [2]