From the MediaBerkman blog:
You don’t need to be a crowned Ranger class master hacker to sneak into someone’s email or facebook account these days. Which means that you’re not simply being a nervous nellie if you’re worried about security.
In fact, users of public WiFi should be worried. If you use WiFi to access some of the most popular email and social networking services, like, gmail, yahoo mail, hotmail, and facebook, your account information floats around in the air, often completely unsecured.
You want some more fear with your coffee? Chris Soghoian, a fellow at the Berkman Center for Internet and Society, took a look into WiFi and account security to find out just how scary the situation is.