Just stashing a whacky idea I had out here while looking at the Baseball Hall of Fame mechanism for determining who gets in. The process is this 1) every player is eligible a set time after their career, 2) they have to get a certain vote percentage (75%) to get in, 3) after a certain amount of tries they're eliminated, 4) if they don't make a certain threshold they're immediately eliminated and 5) voters have a fixed number of votes each round the number of which is relatively small compared to the size of the candidate set.
This process gives every player who ever played a chance, yet trims the pool quickly, and let's voters revise their decision, allowing for some thoughtful consideration. There's also an aspect of competition as you can stay eligible for a while, but you'll be competing against later, fitter newcomers as well.
Could this type of process be applied to media artifacts in a social bookmarking system like del.icio.us? This would be useful for identifying the "hall of fame" posts and highlighting them somewhere. You could also take them out of the consideration pool, so folks don't have to see them over and over. Newbies might get automatically introduced to them. On a per tag basis, this might be quite useful.
Tricky bits: what's a vote and how to deal with voter fraud? And could it be applied to other media artifacts. Or individual, personalized media streams. Hmmmm...