'Tis the season when bloggers, playing out the string between Xmas and New Year's, fill the void with greatest-hits lists from the year just passed. But a question inevitably arises: how does one decide which posts to include? There are many different criteria, and preferring one to another might lead to very different lists. This is what's known as the measure problem in blogospheric cosmology. This year I've decided to confront the problem pluralistically. Thus: here we have five different Top Five lists, chosen according to completely different criteria. Let us know if your favorite Cosmic Variance post of the year somehow managed to not be on any of the lists. First, the most crude and common measure, the posts with the most page views this year.