I wouldn't read that simpering teen girl fantasy garbage unless someone paid me cash up front - and I feel the same about the Harry Potter series and all of Anne Rice's books - however, there are some pop culture trends that you almost have to be living in a cave not to be aware of.
Even if you miss the entire cast of the film shilling the movie with endless banal clips on every chat show on television, there are the banner ads on every other webpage, the drink cup tie-ins at fast food franchises, the t-shirts, the trailers on other DvDs, the comedy show parodies - I mean, they really rub our collective noses in it when they think they've got a hot item going.
That said, I'd be at a loss if I found myself in the middle of a conversation about Twilight, too. But the very mention of the subject would likely send me into a state of catatonic boredom. 