Hello,
I don't know if the developers of PunBB care about this but today i installed a dating script for a customer, it's called AbleDating 2.4 and when visiting the integrated forums admin panel i found a bit of text with "PunBB" in it. So i googled it and found out it's GPL licensed. If i remember right the GPL requires that if you integrate gpl code in your products you must at least state so somewhere and tell where to obtain the sources, right?
Well, isn't something big. Maybe i'm totally wrong... Just thought you would like to know that your forum is used in a software sold for 597$ (http://www.abledating.net/Buy-Matchmaki … K-Soft.htm)