It is based on the rather primitive jforum (Java w/ freemarker for the view). Freemarker sucks though, but I was forced to use it due to the work involved with a rewrite.
The code is extremely heavily modified and is now about 40-50% original.
The wiki is based on jamwiki with heavy modifications and I fed a few major bug fixes back to the core jamwiki code too.
The gallery and other elements of the site are coded from scratch in good old model 1 JSP.
The whole thing goes in to a mysql backend that is holding up very well (innodb instead of myisam).
One day I might make it into a fully open source application, but right now the code is too messy and has too much junk from unused features from jforum and jamwiki so I need to refactor a lot. There are also a lot of hard coded dakka specific things like URLs, security and
DCM related things that dont make it suitable for distribution. It would take me about 6 months of hard work to make the site packagable so that other sites can use it, so I'd have to finish adding features and tuning the site before that can happen which will not be for quite some time.
Thanks for the compliments anyway