Count me as sceptical about the long-term success of Google +, although I do think Google have a better chance than just about anyone else would.
Adding users is one thing, particularly for Google who have been able to create quite a buzz for the launch, but getting them to stay around and use it instead of Facebook is a whole different thing. I was very keen to sign-up and try it out, which i did today, but I have no intention of updating this and Facebook at the same time. And my social network is currently on Facebook. Until the majority of updates from my network are posted to Google+, why would I bother? That’s the problem it faces.
As I say, if anyone can succeed, Google can. But I remain sceptical.