Steam Link App: Will Allow you to stream your Steam Library to your mobile devices.
Press Release: https://steamdb.info/blog/steam-link-and-video-mobile-apps/
The Steam Link app, slated to launch the week of May 21st, allows gamers to experience their Steam library of games on their Android (phone, tablet, TV) and iOS-based (iPhone, iPad, Apple TV) devices while connected via 5Ghz network or wired Ethernet to a host system (Mac or PC), with Android access initially offered in beta. The Steam Link App will feature support for the Steam Controller, MFI controllers, and more across both platforms.
This is pretty huge imo. I've never been a huge fan of game streaming, but I'm really interested to see how this will work, or if it'll have any sort of touch screen controls for point and click styled games or jrpgs/civ.
I've never really watched any movies on steam so can't comment on that yet.
(Nintendo Switch support when)