Because things like "Sci-Fi" (and to a much lesser degree, the recently SMACKDOWN-laden SyFy channel) are mainstream popular, so then are those who consider themselves geeks. When Valley Girls were popular for example, that didn't make you a geek...You were, after all, just following what was popular - much as you are now. Logging into Facebook does not make you a geek either <-- everyone does it.
But I'm not here to argue the denotation and/or societal nuances of geekdom - though believe you me, I could tell you stories, having grown up one. I'll leave those bittersweet tales for later. What I would like to say is DON'T YOU DARE ROLL YOUR EYES AT ME when I mention the score to The Twilight Saga: Eclipse because its an overrated tween vamp movie. Let me explain:
Before Peter Jackson, there were these things called "books" and people would "read" them. The geekier ones read a genre popularly known as "fantasy." Believe it or not, The Lord of the Rings was a trilogy of books long before it was made into a movie and thrust you into geekdom because you enjoyed something mainstream. I'm not discrediting the films - they were magnificent - and I'm not attempting to hold on to a mantle I feel I deserve over someone else either, for as far as I'm concerned, press is great for obscure niches - oh the things I've learned because they were hone from popular culture (I would've never read Vladimir Nabakov's Lolita had it not been for Sting and the Police...)!
One of the things which made The Lord of the Rings trilogy so memorable was its music. The film's "score" or background instrumental music. In this case, the composer of the score for all three films was Howard Shore. His music was so good, in fact, that he won two Academy Awards for Best Original Music Score. This is the same guy who wrote the music to Eclipse. <-- The music doesn't have anything to do with teens, tweens, bored housewives, Robert Pattinson or vampires! Enjoying a grand score by a great composer, is not jumping on a squeeing bandwagon, and when you roll your eyes at the mention of the title, you give yourself away.
So listen, learn, and blend.