A wikiforum is our (self-invented) neologism that we will use to refer to an Internet forum which is hosted on a wiki. It is a means of collecting questions like those that can be asked on a traditional forum and answering them. Unlike threads of a traditional forum, the threads can be sorted into different categories, merged, split, revised or moderated by the readers themselves.
So technically it's a wiki, but conceptually it's a forum, i.e. a public space for constructive discussions around specific problems and collaborative improvement of solutions given by others.