Steam is a good program that allows people to interact with each other ingame, out of games, and in nonsteam games, not only that, but it allows for one to buy a game and download it, possible with discounts not found in stores. There's easy-to-access demos, you can get BETAs, and there "Packages" you can get a specified package of games (Assassin's creed 1+2) for less then both of the games combined together. I've gotton a deal of 5 games combined worth less then the game I wanted to get.