The problem I see with twitter is that there is no "community" verification. There is no real way of knowing who is real and who is just lurking or gathering followers.
I am not a veteran twitter but have spent enough time to notice that you will find lots and lots of users with 300 followers and ZERO tweets or no written posts for you first timers....
The advantage of Facebook is you can tell fairly easily who is spamming and who is real. If the user is some hot chic with big breasts or is wearing a bikini than you can check info to see if he or she is real.
On twitter there is noway to determine if the user is real or not. You are not required to supply any information which I think is a huge mistake in my opinion. As it grows in popularity it will most certainly turn into a marketing frenzy of spammers and sellers. you will have paid tweeters all over the place and because you cannot tell who is real and who is not it will most likely get ugly.
I think facebook should simply turn on a 140 character limited chat section without pictures etc; The reason twitter is so addictive is that it forces everyone to be fast and to the point. Forums and blog require a boatload of time and wordy people waste your time with super long meaningless posts.