A person who co-signs other people's opinions to look knowledgeable. Most jumpshot 23s in fact have very little to no knowledge at all. They often use quotes to make them look even smarter. Also see Kanye East.
Bob: Dude, Limp Bizkit is the shit! They're the best band ever!
Eric (jumpshot 23): I will agree that "Limp Bizkit" is the best band ever.