Reminiscent of a speed freak (aka: the tweeker) it is one who's OCD about memorializing everything they do at any given moment on Twitter; that is, one who tweets incessantly, constantly and/or needlessly.
Posting many "tweets" on twitter (sometimes facebook) in rapid succession, whether said tweets were important/relevant or not.
JoeBloggs: I just ate a piece of cake (10 seconds ago)
JoeBloggs: That was damn good cake (7 seconds ago)
JoeBloggs: Damn, now I'm thirsty, might get a drink (3 seconds ago)
JoeBloggs: Mmm, pepsi. Goes down good (just now)