I think that this movement, as much as anything, it what will speed up the eventual recognition of gay marriage. As more straight people get to know gay people, live next to them, eat dinner with them, they will see that homosexuality (like skin color, hair color, height etc) is just one small aspect of that person.
A couple on new studies are coming out in conjuction with national coming out day. At one time gay people, outside of a few metropolitan areas didn't pubically exist, now 70% of the adult heterosexual population know someone who is gay. In addition, support for gay marriage among people who are related to homosexuals runs 17% higher than support in the general population.
The fact that every year more gay do come out of the closet, and that these people are having a profound impact on the why straight America views gays, is why last summer I said that gay marriage will be accepted as law much sooner than many people expect.