Even Valve/Steam.
http://gimmegimmegam...tion-xbox-users
We’re launching Pure Chess and Knytt Underground later this year, and on Pure Chess we asked whether we could do cross-platform multiplayer, expecting it to be the typical closed console platform I’ve been used to working with for 20 years. Within a couple of days they said, ‘yep, no problem. You can have other console players playing against Wii U players. You can have smartphone players play against them. No problem
Cross-Play with any console.