Skype is a software application that allows you to make voice and video calls over the Internet. Skype already has more than 650 million users (http://en.wikipedia.org/wiki/Skype). And it is also one of the few technologies big enough to be used commonly as a verb, like Google. You can Google information about Skype. You can Skype someone to talk about Google.
One cannot understate the personal and emotional value of Skype's services. Just like those TV commercials you've probably seen for any video calling service that demonstrate how families and military can connect overseas, Skype's video calling can mean a lot to families separated by distance.
You may realize that Facebook leverages the power inherent in our personal relationships; Skype's real currency is love. And no Skype competitor has more than 100 million users, so they have a huge head start in the internet communications race.
The Skype/Microsoft Acquisition
In May 2011, Microsoft announced it would purchase Skype for $8.5 billion (http://www.microsoft.com/presspass/press/2011/may11/05-10corpnewspr.mspx). This extends Microsoft's real-time communication capabilities from text (Messenger, an Internet chat application) to video and audio (http://www.microsoft.com/presspass/exec/steve/2011/05-10Skype.mspx). It's likely the Skype application will be distributed on all new Windows-based personal computers.
In October 2010, Facebook features were added to the Windows version of Skype. In July 2011, Facebook redesigned its chat features. Facebook features were added to the Mac version of Skype in September 2011.
You can now access Facebook and use its features from within Skype. After you open up Skype, click the Facebook tab to see your wall and update your status. You can even apply a filter so that you only see Facebook updates from your Skype contacts.