The occulus rift looks like an incredibly idea, I especially like the games that actually have your hands being rendered in real time, but you can bet it's going to be ruined by facebook because they're going to want to spam the fuck out of you and force you to sign up to it before you can use it at all.
Hopefully there will be several much better copycat versions of it that come out later.
I do not think that Facebook has any incentive to do so. They know the market of the Oculus Rift device well enough that they will not attempt any sort of annoying advertisement. They spent $2,000,000,000 on the acquisition of the Oculus VR company and I am sure that they will do their best to avoid losing customers. Although many may think Facebook is a "bad" company, it is in fact one of the most innovative tech companies in the world today.