Earlier quoted context omitted.
It's a forum. Read the thread and don't have any such concept as a "mention". If you get quoted, you'll see it as you go through the pages. If you're really lazy just namesearch your handle (which may or may not change, may or may not be unique, etc) but basically participate don't just cherrypick. I hate most modern forum software with a passion.
Right, but you would just be one of the rare users that turns the system off. Which is fine, but don't let it blind you to what the typical user wants. "Just use the /search feature to find replies" isn't something I can say with a straight face to the sort of users I have. I would just leak them to competing forums that have good UX. It's no ideal for someone to be unaware that a thoughtful reply was made to a post…
@mentions on forums are good UX in the way that twitter @mentions are good UX - they drive clicks and opens - not engagement. They don't push good content, good conversations, good experiences. They allow people to sandbox discussions, to talk across each other. To skip volumes of content to just get their little piece.
Having the feature degrades the forum community imo, irrespective of who does and does not use it.
I'm a guy who likes old school forums though, so, you know, my opinion is probably not worth that much ;)