It's called "shebang" and a discussion was done on SO few weeks back. http://stackoverflow.com/questions/3009380/whats-the-shebang-in-facebook-and-new-twitter-

It's called "shebang" and a discussion was done on SO few weeks back. http://stackoverflow.com/questions/3009380/whats-the-shebang-in-facebook-and-new-twitter-urls-for http://stackoverflow.com/questions/3009380/whats-the-shebang... Basically the purpose of the shebang in this case is to tell Google how to index pages.