Yes, we've passed Peak Facebook, but that's just because it has been distilled and pornographized to the point of desensitization. Pure capitalism at its finest. What will set the trend for the future is our understanding of how digital slavery works. We can be entering one of the darkest eras of modern history, or one of the most liberating. The choice is up to us, human beings, whether we sell ourselves to whoever…
Like with peak oil you've got to distinguish the US peak (which happened about 1970 though there may be second higher one coming http://en.wikipedia.org/wiki/Hubbert_peak_theory#/media/File...) and a global peak - not yet for oil. Facebook's probably peaked in the USA but has a lot of growth ahead globally.