In the expert-network investigation, the government recorded phone calls of public-company employees such as Mark Anthony Longoria, formerly of chip maker Advanced Micro Devices Inc.
It's a little buried at the moment -- hidden behind the "i" icon in the chat window -- but everyone's favorite social network is now offering a way to place free voice calls to friends.
However, VOIP differs from the usual phone services in that it sends calls as digital packets of information over data networks rather than relying on a dedicated circuit-switched network.