The forum software bookmarks can't do it, they only bookmark the whole thread, not a specific post and there's only one folder.
But you can do it in your browser easily. Make folders there and bookmark per subject, you can even edit names of the bookmarks.
As for bookmarking the specific post from a thread, just click on the posts title.
For instance, zoidberg's post is titled "" and if you click it, the link in the url field (address) will say http://forum.multitool.org/index.php/topic,58841.msg1072908.html#msg1072908
That's the direct link to that specific post. If you bookmark it, it will lead you to that post.