add support for issue tags

I'd like tags in JIRA, like del.icio.us. I saw Confluence recently added a similar feature.

I realise that bugzilla like keywords could be done with a custom field, however I'm thinking of more specific support. Without suggesting too much of implementation, being able to have multiple tag words on an issue, that are individually recognised and can be enumerated as existing tags in places within the system (during issue creation, for project browsing, or as part of a search).