Yes, I was one of those who were affected by the Skype downtime last week, since I use Skype to communicate with my family and most importantly uses skype whenever we have a meeting from our bosses abroad. Good thing, there was no schedule meeting when the downtime occurred.
Skype posted on their blog the cause and information regarding the outage last week. They explained that the problem was caused by an overloaded servers run by Windows client, the crash affected atleast 20% of Skype users and so the blog said.
People using Skype for Windows (version 22.214.171.124), older versions of Skype for Windows (4.0 versions), Skype for Mac, Skype for iPhone, Skype on your TV, and Skype Connect or Skype Manager for enterprises were not affected, the ones that are affected are people who are using version 126.96.36.199, which is being used by 50% of all Skype users worldwide and the crashes caused approximately 40% of those clients to fail.
The problem happened when 30% of the supernode failed, so the remaining 70% is picking up the slack of all Skyper user and at the same time those who crashed are already restarting their client, causing Windows clients to crash and adding that this was happening during peak hours.
Though there were no detailed information on how they (Skype) fixed the problem, there are other technical stuff that skype posted, which is worth reading, so if you have the time, you can read the who article at skype blog.
Last modified: December 30, 2010