I don't think I buy the argument everyone makes about a Facebook presence being obligatory. Are we to believe that the only way people hear of new sites and services is through Facebook? If that's true, then how do people hear about your Facebook page, to begin with? Or is it that they'll supposedly only
interact with your site or service if it's via Facebook? You don't need a Facebook page for people to pass your URL around or mention it in their wall feed thing.
If the idea is that people will no longer bother going to a website or surfing the web in general unless "facebook.com" is somewhere in the URL and/or that they will only communicate with you via forums, wall posts, messaging on Facebook itself and nowhere else, then . . . well, I give up. That's not a world in which I want my service or site to exist and I'd rather not do it at all than do it as some sort of trivial Facebook Serf on their land, by their rules, and with their citizens. If we've come to the point that the entire success and popularity of a service and its continued lifeblood is owed to existing on and interacting via Facebook, then we should wave the white flag and admit we have lost the internet.