To help people understand just how much information can be gathered using sniffers like Ferret, Errata is posting the source code for the tool on its Web site so that developers can try it for themselves.

The best advice that the security experts offered to end-users to protect themselves is to use personal firewalls and VPNs to cloak as much of their information and activity as possible.

"It's not single pieces of information that we're warning about, it's the collection of pieces of data that offer detailed information about who you are," Maynor said. "If the government were collecting this information people would be up in arms, but as it is, they are already giving it away without a second thought."