Here's how it works: at the bottom of every game page, you can see a list of tags that have been applied to that game (and by whom, if you hover over the tag). You can add your own tags with the box on the right. Clicking on a tag will bring up a list of all games that use that tag. Tags can be deleted by the person who added them or an admin.
Features coming soon:
- Authors will be able to delete tags on their own games, regardless of who put them there. This should have been in to start with, but I blanked on it.
- There will be a tag cloud to show popular tags.
- Tags will show up on the gamelist so that you can see them at a glance.
As always, please report any issues or suggestions in-thread.
Edit: If you are seeing a vertical display, you may need to clear your cache (Ctrl+Shift+R in Firefox/Chrome).