Our organization, at least on a field level, really depends a great deal on Skype for cheap communication. But occasionally people ask, "how secure are our conversations." Of course, none of us are chatting about nuclear launch codes, but we do transmit information that's not for public consumption.
I long ago read that Skype data is encrypted, but I never really knew how well. Now German Federal Police are complaining that it's too good:
“The encryption with Skype telephone software … creates grave difficulties for us,” said Joerg Ziercke, president of Germany’s Federal Police Office (BKA)
Sorry about the grave difficulties, but I'd prefer that no one listen over my shoulder. Can people listen in on your Skype call? Nope.