Ah, okay, I give up - what does it mean to "Keep" a thread?<br /><br /><br />Lock, Keep, Move, or Delete a Thread<br /><br />1. Go to your UBB.threads™ community interface, and find the thread you wish to close, keep, move, or delete.<br /><br />2. Click the “manage this thread” button at the bottom of any post. (Users who do not have this right will not see this link.) There is a dropdown menu that will allow you to perform the desired action; click the “Manage” button to open the appropriate screen.<br /><br />NOTE: If you delete a post from within a thread, a placeholder will remain that states the post was DELETED. If you move a thread, you will have the option to leave a placeholder (pointer) as well as an explanation of why the thread was moved.

There is a function to mass delete(prune) threads according to certain criteria (last post date, number of replies...).<br /><br />Kept threads are not pruned even if they fulfill the other criteria.