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.
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.