As part of our ongoing commitment to continually improve the Skype user experience, we developed supernodes which can be located on dedicated servers within secure datacentres. This has not changed the underlying nature of Skypeâ€™s peer-to-peer (P2P) architecture, in which supernodes simply allow users to find one another (calls do not pass through supernodes). We believe this approach has immediate performance, scalability and availability benefits for the hundreds of millions of users that make up the Skype community.
Microsoft - which acquired Skype last May - apparently made the change about a month ago when the number of users logged onto Skype hit 41 million, which is about 37% above average.
Anyway this is good news IMO.