Yup, the forum search should be able to provide you with the answers you seek:
For convienience, these are the links:
An easy overview of you bookmarks can be found in your acount section over here:
I personally wouldn't like my bookmarks to be 'pinned', since I'd have to scroll down for ages to get to new topics since I've got quite a few bookmarks. But feel free to let the guys at Discourse know.