Overtweet (verb) - 1. The transmitting of too many tweets either in general or regarding a certain subject. 2. The #1 cause of unfollowing.
Twilight fans overtweet about their passion for vegetarian vampires.
To tweet excessively on Twitter, to the point that your followers' feed pages are blanketed with little else but your own updates.
Ugh. Sean totally overtweets. I'm going to have to unfollow him