This would make a nice plugin..

[Harry]

Ran across this over at the MYBB forums.. Pretty cool how this guy did this. Could see it being very useful on large boards..

http://mynie.6te.net/demo/index.php

Reminds me of this modification another board did. Was called virtual subforums. That mod made it able to view the forum and JUST the threads you want to see. When someone made a new thread it asked for what region you wanted it listed under. Say you put it under Mid Atlantic. So to see that thread you go to the filter options and select Mid Atlantic or all and it showed. However if it was listed under say midwest then you wont see the thread viewing the forum with the Mid Atlantic filter on. if you have all selected then you see both threads etc.  I believe this modification ( link above )  would have worked better. Instead the site switched to sub forums which a number of people are complaining about. lol

Anyways that is pretty cool how he did that.