[allendoerfer]

I think, they are aware of this, since they already made a few defensive acquisitions. Facebook the platform could slow this by buying the biggest of these and by becoming more of a platform underlying the actual communities. Also at least for a long while they can work on creating new markets (Africa etc.).

Facebook the company has several options to branch out with synergies and create additional revenue streams: Identity and content are the first that come to mind, but there are probably a lot more.

Overall the problem of not being able to grow, because you already have all the users is really nice to have.