Skype has been transparent and open about the cause of the 24-hour long outage last week with a blog post outlining the reasons by its CIO.
The Windows version of Skype had a bug which caused the 24 hours crash on 22 and 23 December.
According to Lars Rabbe, the Chief Information Officer of Skype, the problem began on Wednesday when servers for offline instant messaging overloaded and Skype users began receiving delayed responses.
Users using Skype version 5.0.0152 for Windows were affected as these delayed responses kept piling up and caused the servers to crash. Older versions of Skype for Windows, and the latest version 220.127.116.11 were not affected.
However, 50% of global Skype users were on the older Windows version and eventually the rest of the network was overloaded, in spite of a quick reaction by Skype over the initial crash.
Rabbe summed up, "Regrettably, as a result of the confluence of events – server overload, a bug in Skype for Windows clients (version 18.104.22.168), and the decline in available supernodes – Skype’s functionality became unavailable to many of our users for approximately 24 hours."
He finally said, "We know how much you rely on Skype, and we know that we fell short in both fulfilling your expectations and communicating with you during this incident."
Remember to keep checking for updates folks!