Even the most dedicated fan of a particular TV show can miss an episode. When none of your friends happened to tape the show, what are you to do? You can't just go on to the next week of Lost without knowing what happened before--you would be mystified. Even more mystified than usual, I mean.
Television Without Pity is a wonderful website that provides comprehensive and humorous recaps of a variety of TV shows each week. The day after an episode, a brief "recaplet" appears to tell you the basics of what happened; after a few days, a full, multi-page scene-by-scene recap appears. They are almost always entertaining, whether you've seen the episode or not. Shows of interest to my readership that are covered include Lost, Gilmore Girls, Smallville, The Apprentice, Veronica Mars. and House.
Another feature of TWOP is its incredibly well-moderated forums section. There are forums for the covered shows, other shows currently on the air, and long-gone but brilliant shows. Unlike most internet forums, which are full of fights, grammar mistakes, annoying smiley face icons, off-topic conversations, and in-jokes, these forums are awesome. The moderators rule with an iron fist--when posters are off-topic, rude, or incomprehensible, they get warned or banned. The result is a set of forums that are civil and interesting.