[](http://tctechcrunch2011.files.wordpress.com/2012/05/what-could-kill-facebook.png?w=288)The NaysayersIt’s always amusing to see how the blogosphere and newseratti start lighting up with the most diverse range of concerns when a Valley company decides to go public. When that company is also the world’s largest social network with three times the number of users there are people in the US, things can get interesting. Here’s a selection of the web’s two cents: