Skype You've officially been living under a rock if you haven't used Skype. The Luxembourg-based video messaging platform has been around for a decade. Even my 88 year-old grandmother knows about it. (Granted, she calls it "scope"). Founded in 2003, Skype was snapped up by eBay ( EBAY) for $2.5 billion in 2005. Microsoft ( MSFT) then purchased the video messaging service from eBay and a consortium of private investors for $8.5 billion in 2011. Today, Skype has upwards of 250 million active users. That's not including the Windows Live Messenger users that were converted last month. Skype has a free app, currently among the top 50 downloads in the iTunes app store. The app allows you to place free video calls around the world. It also has an instant messaging service, that makes it easy to share photos or communicate via text. The Skype family also owns Qik video, an app that enables video calling with Instagram-like filters. This free app is compatible with iPhone, iPod touch, and iPad, but requires iOS 5.0 or later. It is also available for Google's ( GOOG) Android.