QUOTE(Kelly Martin @ Wed 24th June 2009, 7:00pm)
Wikipedia will either die in a puff of smoke caused by a nonrecoverable server crash (it'll be brought back up, sure, but any significant downtime will cause a loss of the addicted), or else with a whimper as its content is inexorably reduced to gibberish as vandals increasingly outnumber those who work to stop them.
I think it more likely that Wikipedia will be made irrelevant by a commercial entity. They'll help themselves to all Wikipedia's free content and follow its general model only with advertising and the addition of cash incentives to content contributors and admins.