http://www.psmag.com/navigation/health-and-behavior/women-arent-welcome-internet-72170/
In 2006, researchers from the University of Maryland set up a bunch of fake online accounts and then dispatched them into chat rooms. Accounts with feminine usernames incurred an average of 100 sexually explicit or threatening messages a day. Masculine names received 3.7.
The whole thing is FAR too long to post it in its entirety here, but it is a great read.
