Allow "bookmarking" of forums, topics, and users. Display "bookmarks" in left sidebar (so much empty space there)

I was wondering if it would be possible to add a toggle button (like a star or bookmark) on the top of forum, topic(tag), and user profile pages. If you click the button, a link to #forumname, #tagname, or @username shows up in a list in the left-hand sidebar.

Some of us like a few of the smaller tags, and specific authors. It would be nice to have quick access to them.

Thanks for all your work on this. I know that ideas like this are waaaay easier said than done. We appreciate your efforts. I recommend https://beta.chainbb.com frequently.