You guys missed my point... the serial number would be to show that the board in question was running on the proper site. You modifying oneminuteleft's forum has nothing to do with whether or not the serial number matched the forum to the site.
Crackers have nothing to do with it, the # gets compared against a database that IP has.. even if you found a serial # on someone elses' forum, it wouldn't help you, because the serial # would have to match the web address registered in the database. If the legitimate owner moved his forum or sold the license, it would be their responsibility to update their info at IP... just like it is now.
The complexity added would be virtually nil. Surely anyone able to setup their ubb could add the serial number from their confirmation email into a box in the control panel... that would be all there was to it... it would forever brand the ultimatebb.cgi file, you would only need to do it to that one file.
The serial # would be just a random # generated upon purchase or renewal of their license. They would still need their license # to actually enter the download area at IP. We could go to that complexity here, but maybe that isn't needed.
We get many requests for assistance from people with "new installs" of ubb's a version or 2 back from current. This is something that would take 5 seconds to verify, and an email sent to Bret if the serial #/web address doesn't match.
It's a very simple solution that would fix a lot of the problems we are dealing with in aiding pirated ubb's.