Skype is rolling out advertising in its Windows client in a move that will give it a third revenue stream. In a blog post, Skype said it will begin launching ads in its home tab this week. The company ...

We all know Facebook has 500 million users–heck, it’s even advertised on movie posters now. But many often forget another service that boasts more members than Mark Zuckerberg’s social network: Skype.