I wanted to do a follow-up on the recent Discovery mission, so without thinking I typed nasa.com, and ended up at some kind of directory. I then typed nasa.org, and there they were again!!!! Finally figured out the correct url nasa.gov, but it made me think of how much traffic that directory must get...
Type in domains can drive boatloads of traffic - these guys have it down to a science: http://www.digimedia.com/