The Pavlina forum, I have noted elsewhere, goes through similar cycles. There are insightful spikes, then a degrading of discussion. The last low cycle was defined by "blow jobs" and "anal sex" accompanied by a spike in posting sexy pictures.
This cycle is easy to recognise, and you'll notice a good number of the more spiritual members begin to disappear for a while. These symptoms indicate a return to the lower chakras due to insecurity from events at the time. Any time groups want to return to "happier times" via nostalgia and "the familiar", you can take that cue to look to higher cycles and see what's going on, there. Energy study is so very interesting.
During Thanksgiving, my brother-in-law said I was "brilliant" for leaving Facebook. Coming from him, that's quite a kudos. He and many others I know are getting pretty tired of the pettiness and shallow exchanges: they've become hungry for more meaningful things, and no wonder: there is not much nutritional value to Facebook.