Bookmark really works for all these things so far you don't clear it along with all your entire data (if you do clear your browsing data).. most cases of clearing browser data won't do anything to your Bookmarks if synchronised to cloud(unless you manually clear it).. You will see the distinct layer between Bookmark synced already and the ones that only sticks to your device memory .
The problem of bookmark is when you have so many thread bookmarked, you will be hard to find the specific thread you're looking for. If you only remember the content of the post and forgot the topic title, you will likely to click all the topics.
Bookmarks can be named, you can put a label or a specific message on them when you are naming them. So I don't think it'll be that hard to find the post or topic you are looking for. I have been doing it for a long time now I have no trouble looking for threads/posts that I have bookmarked whenever I look for them.