I’m pretty much addicted to it! I think pretty much everyone I know that uses it starts off with the view “I don’t get this” - I did, I couldn’t really see the point, but I had to teach people about it at work (really!) so I needed to familiarise myself with it, so I got an account, started following a few people and got hooked.
I use Facebook and Twitter in completely different ways - Facebook for me is for keeping in touch with people I actually know - I don’t add people who I don’t know in real life. Twitter on the other hand I use to talk to people I don’t know - in my case this is largely web designers. The thing to remember about Twitter is that a lot of people have set up views that show them all tweets by every user with a particular word in. I do web design using a language called coldfusion - I found that after posting something about coldfusion, loads of people started following me because they’d seen my tweet this way, when I visited their profiles I found that they were posting useful things so I started following them back. What you start noticing is that people reply to each other (posts with @username are replies), and if you follow both people then yes, you see the whole conversation.
I suggest if you’re not sure, to get an account and post a few updates. Maybe search for a few famous people you’re interested in - a growing number of celebs, musicians, writers, politicians etc have twitter accounts, add some news feeds (I have web magazines such as .net, new scientist etc) and suddenly you’ll find you’re hooked
Oh, nearly forgot: top tip for finding interesting people: use this URL http://search.twitter.com/search?q=femaleforum and replace femaleforum with whatever you’re interested in to see everyones tweets on that subject