"Favor" is the wrong word, but only because that implies a lack of payment. Quoting from https://news.ycombinator.com/item?id=18411779 :

> 2009 - NSA offering 'billions' for Skype eavesdrop solution [1]

> 2011 - Microsoft buys Skype for $8.5 billion. Why, exactly? [2]

> 2012 - Skype replaces P2P supernodes with Linux boxes hosted by Microsoft [3]

> 2013 - Microsoft handed the NSA access to encrypted messages Subhead: Skype worked to enable Prism collection of video calls [4]

> 1. https://www.theregister.com/2009/02/12/nsa_offers_billions_f...

> 2. https://www.wired.com/2011/05/microsoft-buys-skype-2/

> 3. https://arstechnica.com/information-technology/2012/05/skype...

> 4. https://www.theguardian.com/world/2013/jul/11/microsoft-nsa-...