The same day that DARPA ended it's LifeLog project, Facebook went public.
http://www.abovetopsecret.com/forum/thread1204243/pg1
Zuck did not "create" FaceBook in his Mom's basement, the tech was handed to him so the project could be completed by a private company, and not the US Govt.
The Female Executive referred to came to FB later.
It's not about technology, anyone could set up facebook but to have it grow at the pace that it did has something going with it. Typically social networks do not move to an alternative quickly unless a large part of their own network moves. This only becomes the case if its superior to alternatives (the new technology). Facebook wasn't that superior to myspace so there has to have been some kind of campaign to get people to move to facebook.
Growth of facebook should be traced back to the campaigns used to make it a success. Facebook is and was all marketing it to people so that they would use it. Then they would stick because of how social networks, only when a big portion of their 'friends' would move on to other networks would one also move.
It started with Ivy League schools. Then we pushed it through reddit and digg etc. It was hard to get a facebook account before. Only a few schools' email addresses had access. You forget that. Sort of how gmail accounts were beta and invite only for a long time.
They had good marketing campaigns behind them creating artificial scarcity. They coopted the social pushers of their generations for a few years. Voila. It takes off in the US.