Really, you can't imagine anything? You can't imagine a good thing someone might want to do over a network that is (well, is meant to be anyway) completely anonymous? Seriously, right now with Arab Spring going on, Syria shutting off the internet, China having the biggest firewall, other countries fiddling around with censorship, people going to jail for tweets or clicking "like" on facebook and you can't think of a valid reason one might want to be able to hide their online activities from prying eyes?