My theory: Tons of supernodes (static ip with no NAT, broadband, constantly on) are in the 20s-30s age group and are on holiday. Plus office and university machines that are normally left on have been turned off. The people I know in universities across Europe normally have skype on at work constantly, or at least during the day, and most have static ips on their uni networks so I imagine they get selected as supernodes quite often. I know many uni network admins have complained about skype using bandwidth. All those people just went on holiday over the last week or so along with all the people in uni dormitories. I'd expect that would have lost Skype thousands upon thousands of supernodes. Add to that an increase in calls due to the approach of Christmas; calls that are personal and use video and audio rather than just audio (which is more common in business usage patterns during the rest of the year). Holiday gamers turning off skype to stop lag would factor as well (doesn't matter if it's true or not, gamers blame everything but themselves during losses and would no doubt turn off skype). So a 20% or more drop in supernodes, 20% or more increase in calls and bandwidth, plus holiday torrents/youtube/hulu on the remaining nodes slowing them down and you have the perfect situation for this.