WoW, are based on older games (often completely different types of games like an RTS or RPG) with a rich mythology that lends themselves perfectly to transcend its original form and become an MMO. Others, like Age of Conan and Star Trek, have their origins in novels, film franchises or even a TV series. I know, I know, I'm still waiting and living in hope of that Firefly MMO just like the rest of you.
So my question for you is this: Do you play an MMO because of where it came from? Are you a Trekkie who is dying to captain your own ship? Did you play Warcraft back in the days of The Frozen Throne and gravitate naturally to the MMO? On the flipside, did the lore of LotRO make you want to read Tolkien's books? For you, what came first, the origins or the game?