My parents went to go see the Day the Earth Stood Still last week... and all my mom had to say about it when I asked her was "Have you read the Watchmen?" She'd never heard of the movie before, but saw the trailer before DESS and liked it enough that she didn't even bother talking about the movie she had actually seen. She's never really read comic books, but she is an avid reader, so she asked to borrow my copy of the book and I gladly obliged.
Just another antecdote about the hype of that movie-- it's powerful enough to appeal to most people, and yet it's not a comic people have heard of. Even if you're not a comic book nerd everyone knows about Batman, Superman, Spiderman... but nobody knows about the Watchmen. So they see the trailer and it garners interest to read this mysterious novel that somehow slipped by them unnoticed.