The tags would need to be handled carefully though. Let any user create them on a whim, and you have a complete mess of nearly-duplicate meaningless tags. Only

The tags would need to be handled carefully though. Let any user create them on a whim, and you have a complete mess of nearly-duplicate meaningless tags. Only have a rigid set of tags, and you'll find some things just aren't covered well by the existing tags. It takes a continuing system of moderation to gradually revise the tagging system over time to get anything good out of it.