Stealing session cookies from other computers on your local network is now as easy as clicking a button. We now have a Firefox extension that sniffs for non-HTTPS cookie requests on your current WiFi network. Login as that person by clicking a couple of buttons.
http://codebutler.com/firesheep
I need to bring my laptop to work and try this one out. The ppl/wifi density in the center of Osaka is amazing. However, I don't see FireSheep setup for snagging any Japanese SNS network log-ins.