Facebook is the new MySpace

I have been reading a report to the OCLC on people's use use of the internet and what has stuck out for me is that how quickly things can change in social media. The report was written in 2007 while MySpace was "THE" social networking site. Then in 2008 Facebook overtook MySpace. Now, according to Alexia Facebook is ranked 2nd in Alexia's top sites and MySpace is 164 (according to traffic rank).
It makes me realize how important it is to have the most up-to-date information on websites before deciding which sites to use professionally. Based on the 2007 MySpace would be where libraries would go to meet the most users, but in the space of a year all that changed. Of course, the largest audience is not the only basis for for evaluating a site, but having an on-line presence where people already are, is important.