How Does Skype Work?
Jaan: Skype is a piece of software that you can download for free and install on your computer or Windows Mobile device. It can then connect to other Skype users directly over the Internet through something that we call the “Global Index” and this is really the heart of Skype. This means that every computer running Skype can very easily find out who is available on Skype, regardless of their location, and can then connect to them regardless of wherever in the world they are. And there is no central server, the whole thing manages itself dynamically as people come online and go offline. So when you call someone, the computer finds out if that person is online, and if so, a direct connection is made to their computer and the call is connected, establishing a direct voice channel. If the other person is not online, then you can leave them a voicemail that gets stored in our voicemail servers and is delivered when the remote party comes online, or you can also get forwarded to their mobile
