Luxembourg-based Skype has now been downloaded more than a half billion times, averaging six downloads every seconds since it first launched 42 months ago.

This cements Skype, an instant message and voice chat application, as one of the most downloaded voice-over Internet protocol (VoIP) apps. In total, there are more than 170 million registered users. "The entire Skype team owes its success to the global community of registered users we have today who tell their loved ones how much they enjoy using Skype. We’re absolutely delighted that so many people are embracing Skype and speaking to friends or family all over the world for free or very little cost." said Skype CEO and co-founder Niklas Zennström.

One of Skype's main features is the ability to use it as a virtual phone, which allows users to call any phone number in the world for a nominal charge, as well as to other Skype users for free. According to Skype, "Skype to Skype minutes" in the last quarter of 2006 alone totaled 7.6 billion.