Using plugins like "Members" or "Capability Manager", I don't see any such manage_tags capability. Shouldn't there be one like there is manage_categories?
EDIT: I think I figured it out. manage_terms is for all taxonomies. There isn't one specifically for tags, but I could create one if I so desire. This could allow me to set up a role that can edit only categories, but not tags, and vice versa.
NOTE: I got rated down. If you rate me down, please state why. Thanks.
