[Brad]

Well vBulletin already scans the thread table elsewhere in the same manner, and your always going to take a shot in load with such a feture. You could store the data elsewhere but why waste clockcycles making a copy of date or removing it to manage the virtual forum?

The best way would probbly have to be managed by moderators, via check boxes ethor in the thread or on a seprate moderation page for the thread. In this space the mod could assign the thread to virtual forums they want it to display in. This would invoke a update function which would write data to a new field in the thread table.

Then it would be a matter of writting ethor a modification to forumdisplay.php or a seprate php file in which you would query the thread table for data based on the new field we added.