The .plan file of Ryan Gordon of Icculus.org outlines a project he undertook to create his own tags for his game collection on Steam. The result is Steam Tags, which will allow you to do the same, described like this: "Basically, you go there, you tag your games, and then you can filter them by those tags. Click the game to launch Steam and install/play the game. Tags follow you from computer to computer. It's that simple." This will require a little trust, however, as you will see this message when you attempt to use this: "You need to log in to Steam Community to access this page. Your password will only be supplied to the Steam website. This website will never have access to your login information."