Board Thread:New Features/@comment-5098825-20160226220004/@comment-168424-20160301230150

Elexorien wrote: Maybe this does what you're asking? I don't know if it's only for Admins + Bureaucrats though.

That might be part of what the OP wants, but they want a tag to appear based on how long a user has been at the wiki (based on first contribution?).