You may or may not be aware of Firesheep, a Firefox plugin that makes it ridiculously easy to commit identity theft. It was released about the same time EvisceratiNet went live, and had about 200,000 downloads in the first two days. I just found out about it yesterday.
Here's the short version: when you sign in to most web sites, the web site will mark you as logged in by placing a cookie in your browser that essentially says "yeah this guy's OK." Most of these cookies are unencrypted -- that is, there are no particular safeguards against another browser reading and/or using that cookie other than it's being sent to you and the general expectation is that it won't be intercepted and used by anyone else.
However, if you're getting these cookies over a wireless connection, especially a public one, it is actually possible, and apparently very easy, for anyone with the right equipment to collect any cookies sent your way. Firesheep does just that. When you activate the plugin a new bar appears in your Firefox browser with a list of every insecure cookie it finds. And if you click on one of those cookies, it logs you in to whatever service the intended recipient of the cookie was trying to access.