It's now even easier to buy too many games from Steam. Valve has implemented remote downloading, allowing you to manage your PC's Steam collection remotely, from anywhere you can access the website or mobile app. Remote downloading lets you start a download on your computer from any of these other sources, and have them "installed and ready to play on your arrival." In other words, you can buy a game from the mobile app and have it download automatically to your home PC, or reinstall something else from your Steam collection remotely. The Store will even ask you upon purchase if you'd like to remotely install your new game, if it notices you're shopping from away from your computer.
Source: Steam enables remote downloads from web or mobile | Joystiq
