Based loosely on a line from the ever-quotable Andy Warhol: "In the future, everyone will be famous for fifteen minutes". Or something like that. It's used to describe the fame of a one-hit wonder, for instance, or of a person whose fame comes from a short-lived event - Amy Fisher, Sister Souljah, Charles Perez, Dave "Puck" Rainey, Jesse Camp, and those septuplets are modern examples. Or annoying multi-hit wonders, like Britney Spears. In internet time, there's "15 seconds of fame" - "push", anyone?