[misuse-permit]

This still doesn't solve the problem of helping users discover what tags are out there. I didn't even know about tags like 'discussion' or 'support' until I read this post, and I wouldn't have thought about typing them in to see if other people are using them because they seem somewhat obscure.

[AgentConundrum]

The 'discussion' and 'support' tags only apply to the meta sites, not the main Q&A sites. When you post a question on a meta, you're required to tag it with one of four tags which help the mods/admins filter the purpose of the post - bug reports, feature requests, open discussion, and support requests.

If you've ever made a post on meta, this would have been made obvious since the tag input box comes prepopulated with a list of these, and the submission fails if you don't use one. If you don't post on meta, however, these tags are meaningless to you.