The hashbang was a stop gap solution for helping search engines see ajax content. The companies that had turned to hashbangs, have just as quickly turned away from using that technique because it's a poor hack, not a well thought-out solution with a roadmap forward. pushState is the, apparently, likely path forward (Google for example has put its weight behind that approach over their previous support for hashbangs - http://www.youtube.com/watch?v=yiAF9VdvRPw).

The # is still very widely used in urls, for direct linking to a part of a page for example.