Based on the Japanese form of keitai shosetsu, or "cell phone novel", a twitter novel is the newest form of serialised fiction on the interwebs. The 140-character limited format and method of reading bottom-to-top offers great opportunities for experimentation within the novel form and makes the reader pay more attention than they would with straight-ahead dead tree fiction.
vermilionsands02: dude, have you been reading teenage_exiles? that twitter novel is deep!
dr.benway13: i know! what a mind fuck!
A message or anecdote that spans several successive tweets, each individual tweet akin to a page of a book.
A bitch to read, and even more so to type out, especially if its an @reply
A: Did you just see that Twitter Novel from Mark? That thing was like 5-6 tweets long!
B: Yeah, what's the point with this stupid 140 character shit anyway?