It didn't. It's been bubbling along for a long time (Facebook launched in February of 2004 ~ http://www.facebook.com/press.php ) Facebook is also doing a lot of things right, namely Connect, Connnect, Connect. The mantra of the new, post multi-tasking adoption of the always connected. For example:
- choosing a demographic (gen z) that values communication as an opportunity
- attaching themselves to organisations that are already wired and communicating (schools & universities)
- choice of technology (open) ~ http://developers.facebook.com/opensource.php
- continuous innovation ~ http://blog.facebook.com/blog.php?post=2207522130
- enabling ~ http://www.cit.cornell.edu/policy/memos/facebook.html
- and finally, making something that people want and the best tool to do this at the same time!
Of course the story on Facebook is still being written. Zuckerberg is really taking the long term view for Fb with a $USD12M dollar funding (and the service shows this money well spent with lots of details covered, api, reliability, etc ~ http://tinyurl.com/2ug3p8 ) When the market cools and users wane (a'la Friendster) will the reported $USD1B offered by Yahoo! and rejected, be seen in hindsight as a good idea?
Then when the time was right, they opened it to all.