1. The first is that with respect to all its services, a detailed record of who is communicating with whom is now kept, and clearly it is being shared. Before Microsoft, back when Skype was purely a peer-to-peer service, I don't believe they kept those records except in the aggregate.
2. The second is that with respect to text communication, it now appears that a copy is retained on Skype servers... because this is the way they can guarantee delivery to those that are offline at the time text is sent. I still don't think Skype is retaining a copy of the encryption keys, but the very fact that they could potentially hand over a copy of the encrypted text is alarming. Nobody knows how well encrypted it is because Skype has kept that a secret._________________________
Skype Considered Government Requests With Project Chess