Ask HN: Has 'facebook' become an un-genericized trademark?

We're all familiar with genericized trademarks -- terms that once were trademarks but have become the generic term for a certain product, like aspirin and escalator. I'm wondering whether the word "facebook" -- which was once the generic term for a directory of names and faces -- has become the reverse: an un-genericized trademark. I would define an un-genericized trademark as a term that is so strongly associated with a particular product (in this case, the social networking website Facebook) that anyone who encounters it assumes you're talking about the particular product, rather than the generic term. This has practical consequences. Typically, a company can't exclusively claim the right to use a word that it did not create; in the case of "facebook," the term had been in use well before Facebook's founding. But might Facebook be able to claim that "facebook" has become un-genericized, and thus argue that no other site or product should be able to use the term? What do you think, HN?