Over the last 12 months, games such as Rocket League, PlayerUnknown's Battlegrounds, Dauntless, Paladins, Smite and Realm Royale have enabled PS4 cross-play with other consoles. Xbox One and PC gamers will be able to face off against their PS4 buddies in Call of Duty: Modern Warfare later this month too. Some other games -- including Disc Jam, EVE: Valkyrie, Final Fantasy XIV and Street Fighter V -- let PS4 and PC gamers play those titles with each other.
Sony didn't have a splashy announcement about bringing cross-play out of beta -- it revealed the news almost as an aside in a Wired story about its cloud gaming ambitions. A number of other major titles offer cross-play between non-PS4 platforms, notably including Minecraft and Roblox, so it'll be interesting to see which developers embrace Sony's new-found openness.