I'm sure it was some combination of everyone working together and the bad PR, but Google uses them as the default registrat for Google Apps domains.
Threatening to change that arrangement would have a continuing impact on their revenue, rather than being just a one-time outrage. That gives Google more leverage than the other sites, which is why I wonder how that played out.
But make no mistake: I'm very glad to see all the websites out there banding together to fight this. Reddit, Wikipedia and even Cheezburger created enough bad PR that they couldn't ignore this and we have to give them credit for that.
