Well, I found out that it will tell you that it has been bookmarked and gives you the option to return to the thread. If you don't select that option, the bookmark does not show up - at least not for me. My last one did show up after I selected that option, but many others are simply not there.
It might be that the message shows up too soon, implying that it has been bookmarked when, in fact, you MUST return to the thread for the process to complete.
I dunno. You would think that if you get a message saying the bookmark has been added that it would have been added. I'm not whining about it. I'm just observing it.
go to your FR homepage.
select the option "links"
a hotlink+URL list of all the FR bookmarks you have made will appear