That wasn't the insight. Google+ did more real identity than Facebook.
I'd say Zuckerberg's crucial insight was "people will still use a social website even if you don't let them customise the look of their page".
That wasn't the insight.
Peter Thiel who is on Facebook board of directors and who invested in Facebook very early argues that's the critical insight.
The fact that you can't see from the outside that's what drove Facebook is only more evidence for it being a nonobvious insight where few outside people agree.
Google+ did more real identity than Facebook.
Google+ was released a lot later. With Google+ it's also quite easy to register an account under a fake name which wasn't true with facebook in the initial days.
Another month, another rationality quotes thread. The rules are: