We reported just last week that the Steam Store now had the option to tag games to create a more powerful shopping experience. The problem was, it didn't take long for the most bizarre, unhelpful and spoilerific tags to appear on the store.
Starting from today there is an option visible next to popular tags on game pages which allows users to report the tag and downvote it as well.
One of the following four need to apply before Valve will then remove it from the page; offensive/abusive; not appropriate for the product; spoiler; or simply not helpful.
You also need a larger amount of users tagging the same thing on a store page before it shows up as popular - hopefully preventing the spam from occurring as often as it did before.
The Steam Dev Team have said "Please keep the feedback coming, we're continually working to improve the feature."