It seems that Carnivore isn't as selective as the FBI thinks...

Carnivore is the FBI's email & web monitoring software, which the US Government is attempting to have installed on the mail servers of every ISP in America. It seems that instead of capturing data from a single, specified source, it has been capturing data from additional unauthorized sources.

Of course, why they don't just tap into Echelon or Echelon 2 escapes me. (Aside from the fact they don't want to acknowledge the existence of Echelon/2, despite the plethora of evidence)