Long time passing . . .
Hm, I'm deviating.
No is this just temporarily or are they definitely gone?
Well, where you clicked that extra icon near the flag bad post icon, to mark that thread.
Oh, so instead now you click the bookmark icon at the top left of the post.
You can retrieve all your bookmarks from the top Finder menu --> Posts I've Bookmarked.
OK, so I'm not quite sure which you're referring to, but you have two options:
Click the bookmark icon to the left of a post to bookmark that individual post.
Click the pushpin icon to the left of the first post in a thread to pin the entire thread to your bulletin board for watching :)
Either way, you can get to your list of bookmarked posts or watched articles from the new Finder menu.
OK I see, well: solved then. :)
Took just about 20 secs to find the solved button on top of this thread! :)