This guy described what I think about the emerging G+/FB war better than I probably could.
… the Circles team lead had said:
“…[We know] the danger of this, but were counting on the fact that facebook wouldn’t be able to change something so core to their product. [adapt to Circles model]“
I had originally assumed that he meant facebook would lack the agility to make the necessary technical changes, so central to their system. But I was wrong–the real point was that they would not be willing to change direction so fundamentally.
Now, I’m not saying that Circles is the one killer feature to bring down facebook–not at all. What I am saying, however, is that these two products are not playing on an even field. Like Microsoft and online Office, it is incredibly difficult for facebook to make fundamental changes to their product suite to answer competitive threats. It is for this reason I feel that Google+ has a genuine shot at dethroning facebook.
My theory is exactly same: FB won’t change something so core to their product. Look how they mimicked “following” with their pending friend requests.
On the other hand one big advantage that FB has is its maturity in social science. G+ is still a pure technology play around Circles model. The real question in the long run is who’s better at innovating in both technology and the new social model of online humanity.