Nobody is forcing you to use it, but there's a lot of interesting stuff on there, even if you don't follow people it can be really good to search when there is breaking news, because almost all the time there will be someone tweeting from wherever it's happening. It's obviously becoming an invaluable resource for this because real news agencies are getting information from itWhy would I care about most of it though? Any big news will be in... the news. No celebs etc have ever said anything I've been remotely interesred in. If I want to talk to people I know I can phone them or even facebook them. At least with facebook it's a bit more personal and there's a good chance for an actual conversation.
I communicate a lot more with people I know through twitter than I do through facebook, but that's possibly because the people I talk to use twitter more than facebook, we've been using it among my group of friends for maybe 3 years, especially when it was much smaller and the mobile stuff worked initially it was great for replacing group texts.
I think twitter is a lot more personal as usually you're using it a lot more like chat if you're having a conversation with someone, but I'd rather do that and have it drop off the bottom of my twitter feed than have a sprawling comment conversation on facebook. Horses for courses obviously, but you're daft to just say twitter is **** without really knowing anything about it.