Say farewell to Mo Koyfman, the IAC executive dropped in to monitor the crazy kids when Barry Diller's internet conglomerate acquired College Humor. He's resigned from his position as chief operating officer of the dorky web site. There's nothing particularly amusing about the news, except for the assumption that Koyfman represented adult supervision. Founders Josh Abramson and Ricky Van Veen were always substantially more straight-laced than their reputation for rampant loft parties would indicate; while 30-year-old wannabe modelizer Koyfman, however engaging, is as much a grown-up as Barry Diller is an internet guru.