I am a Twitch partner and just last week I received a survey asking me my thoughts about affiliate marketing in regards to promoting free to play games, selling games, and relate peripherals. Seems timely now.

What questions were they asking?

Amazon does do digital downloads of games.

http://www.amazon.com/Game-Downloads/

All of the top Twitch streamers have revenue sharing partnerships with G2A.com, a digital download videogame marketplace. It will be interesting to see if Amazon pushes their competing offer.

Amazon already sells downloads. They aren't a huge player in that space, but they do have a foot in the door.

... Valve should have thought of that. That said, Valve tries to avoid the whole business side of business.

Valve has no need for adding on a hugely expensive live streaming site. Steam has very little serious and threatening competition and their own IPs (Dota and CS) are raking in cash along side their marketplace. They are doing well now and don't have the same stock holder expectations for growth as a public company would.

Amazon sells digital games.