Have a page where a user can view and manage the topics that user is watching, rather than having to search around and find and forget individual topics (it could also serve as topic bookmarks).
This page should include, at least, the titles and links to each watched topic with an "unwatch" button for each. Maybe listing how many posts there have been since the user last viewed it. A filter should be included so one doesn't have to scroll through several pages of topic links. A topic search to add more topics could be included, but can be done elsewhere on the site.

This is a very good idea!

I agree, this seems like a great improvement to the site.

I also agree with this. It sounds like a great idea and I know that this would at least definitely be very handy to me.