Tags are Descriptive Keywords associated with maps and mods.   They allow you to find releases that contain the type of content you enjoy, irrespective of the game.

The tags used are very selective.   For example, there is no point in having a "headcrabs" tag as most maps and mods have headcrabs.   However, the "crossbow" tag IS useful because not many releases have it and it offers very specialised gameplay.

Some tags are game specific, for example, Hunters only appear in Ep2 releases.   However, many tags are relevant to all games.

For more information, please see the Tags Guide.