I would like to weigh in as a person who has been around DNN for quite sometime and have seen it changed.
I think having the forums locally on Dotnetnuke is a wonderful thing. I like the centralized approach and I use the forums alomst daily to find and answer questions when I can.
As has been stated before most questions are simly new users who don't want to take the time to dig into DNN and actually learn how it works. However, there are a series of in depth questions regarding programming that if answered would take someone replicating your development enviroment. It just isn't possible or resonable to think that someone is going to spend their time answering those type of questions.
As a DNN developer I have been there, struggling with understanding how to accomplish something the "right way". I find looking at blogs and post of those DNN hardcore users helps to explain concepts that are completely new to me.
Finally, the one major problem I find with the forum and with DNN in general is the search functionality. It just doesn't work and is cumbersome. I rely heavily on http://www.searchdotnetnuke.com/ to pull the information out of Dotnetnuke that I am looking for.
In a past life I was a network administrator and when I first started setting up core switches I found myself reading a lot of manuals, posts, blogs, newsgroups, etc in order to understand how those bad boys worked. Once you have learned the basics then you can start asking meaningful questions that get to the point and are answerable by people.
Just my two cents,
Stuart