I created folders. It is an option in the Bookmarks feature. When I bookmark threads, I get a drop down menu of my folders and can place the thread into the appropriate folder. I have Poetry, Grammar, Spelling, Vocabulary, Lit Responses, Novel Titles, etc. When I go to My Desk, my folders appear in a sidebar and when I open a folder, there are all the bookmarked threads in that category.
You can also place entire threads or single posts into Collections or into a Scrapbook ny clicking on the scissors icon on the top right corner of any post. You first have to set up your collections by topic. I use the same topics I have on my flash drive (subjects or curriculum areas.)
TIP: When you find a helpful post on the boards, Click on the scissors icon to clip it to your Scrapbook! From your Scrapbook, you can print items or sort them into convenient collections, which can be kept private or published on proteacher.org!