It's run on an older and highly-modified version of ubbThreads.

Virtually no large communities run this software any more for numerous reasons, one of which being that the company virtually abandoned support of this software up until about a year ago when they suddenly decided to release a new version.

We've examined the new version and are not impressed with the usability and functional changes they've made, so we will not be "upgrading." We're more likely to go to better supported popular forum software, such as vBulletin (powerful, but harder to customize), phpBB (not as powerful), or Simple Machines Forum (SMF).

But we have no active plans to do so at this time.

DocJohn