Valve do like their user-generated content. They've updated Steam with Steam Reviews, Steam Greenlight and now Steam Tags, which let players label Steam games with keywords. Those tags are then made searchable and used to recommend game-types you might like based on your playing history.
Unfortunately, much like previous additions, it turns out the internet can't be trusted. The system is already being used to mark games with insults, and even though it's still in beta, labels are already appearing on game's store pages.
In theory, Steam Tags are a great idea. Given that Steam is now home to thousands of games, with hundreds more being added through Steam Greenlight all the time, better ways to search the store and database are extremely useful. It means you can filter for only games that are "color-blind friendly" or "singleplayer, RPG, Linux" or "༼ つ ◕_◕ ༽つ". If you look at the overall most popular tags, the list is mostly useful.
Unfortunately that's not the case if you look at the most popular tags for individual games. Fez's top tags are "choke on it", "choking hazard" and "Diva Dev", which means those three appear on the main store page. If you click through to the full list of popular tags attached to almost any game in the store, you'll find a lot of objectionable langauge or comments. Kairo has "giant piece of shit". Hate Plus has "gay agenda." Gone Home's most popular tag is "not a game." The Actual Steam Tags Tumblr is filled with examples.
In the FAQ on the bottom of Steam Tags site, Valve pre-emptively address a couple of these points. The system is still in beta because "We need to get some data into the system before it will be fully optimal. That means the initial categorization of items might be a bit off until we see what kind of tags are becoming prevalent and tune the system for the best results." "A bit off" was, I suppose, a nice way of saying, "a lot of you are going to smear every game with evidence of your infuriating ignorance and cruelty".
They also address the issue of offensive language, stating that, "Swear words will be filtered out and not appear among popular tags." Which makes it confusing that "shit" comes up quite so often. Even if that word gets filtered, I'm curious how they'll stop the more subtly mean tags without active moderation. Valve traditionally resist solving problems by hiring people, relying instead on crowds to do the work for them.
I can understand why - the broiling masses scale better than building a factory of support workers - but if I was a game developer I'd be appalled by people being able to smear my Steam store pages with whatever hateful nonsense sluiced out of their brains. Even if not outright offensive, labeling Gone Home with "not a game" in an official, influential place like Steam is regressive in a way that stunts the medium. Valve suggest that "Tags can be a good indicator of when there is a mismatch between how you perceive your game, and how your game is perceived by customers," but that doesn't seem fair to me. If nothing else, you don't have to buy a game in order to tag it, so we're not just talking about customers.
Calling Team Fortress 2 a "hat simulator" is pretty good though. That's fair.
Steam Tags is currently in beta, so the system will inevitably change in the days, weeks and months to come. In the meantime, you can provide feedback via the Steam Tags discussion forum.