Gamasutra has word that the Human Head/3D Realms title Prey will be digitally distributed in a manner similar to the Steam service
, though not over Steam itself. The Game xStream service, the chosen distribution channel, seems to offer improvements over Steam as well as convenience. From the article: "Gamers will be able to pre-order and pre-load Prey onto their hard drives, ready for instant activation and play upon the official release date...Or, after the official release, players will be able to buy the game and begin playing in minutes, as if the full game was already downloaded. This is what sets Game xStream apart from anything else the industry has seen."