I think social networks are cyclic because they have a 'fashion' element to them. Whereever the 'hip' people are that's where the rest will follow. So once the 'hip' people (some would say the trend-setters) move out their groupies will follow. Of course after that it's a long way down that hill that you can literally shoot up on but I don't think there ever will be a permanent social network. It's more like a locust…
I do agree with you. But if you view it this way, are't most systems cyclic? companies, economic boom and burst. Even America might fall one day after its peak. The important question is how long the cycle is. Previous social networks have never gained such mainstream adoption and user participation as Facebook have. Facebook might fall one day, but my bet is that it's gonna take longer than you anticipated. Everythi…
And sure, everything is eventually cyclic (well, almost everything) but I mean cyclic on a measurable (say 10 years) time-scale, not something geological.