Looking to improve upon the Steam experience, Valve has introduced Steam Tags as a "powerful new way to shop for games." Currently in beta, Steam Tags allow you to apply tags that you think are inappropriate or relevant to a game. Tags that are applied frequently will become "featured categories," helping people find a new set of genres, themes, and attributes "defined by you and the rest of the community."
Steam Tags will allow you to apply tags with terms that you think are appropriate. Tags can range from genres such as "Puzzle" to themes like "Military," or even attributes like "Difficult." Alternatively, you can come up with entirely new concepts for categorizing products. You'll then be able to browse the Steam catalog by popular tags or by tags recommended for you based on games you've played recently.
As of right now Steam Tags is in beta. If you're interested in checking it out you can opt in to the Steam Client Beta which lets you see the latest features before they're released.
