[allendoerfer]

Google tried something like that. The whole circle idea was about control for the user of who he shares stuff what content with.

Facebook cannot be killed with something so similar to Facebook like Google+, much like Google cannot be killed with something like Bing. They are at a local maximum amassing lock-in and buying up every improvement on the status quo.

What might ultimately kill them is either EU regulation, a big Chinese domestic market or some jump in technology or business model. The end result might again look very similar to what we have now. I think in the beginning it would start out as something like Whatsapp or Siri. It could be something that takes over or kills advertisement completely like Amazons various tries to create a platform for all online commerce.

[prapam2]

Whatsapp was a good strategic investment. Most of my friends spend more time on Whatsapp then facebook.

[allendoerfer]

That is why I said something like Whatsapp could have been a potential Facebook killer. Imagine them gaining users quicker than FB - what they did - and carefully branching out to take usage time away from FB - what you described.