This forum has evolved almost entirely into technical post-production questions. A few months ago, there were some questions about guerilla filmmaking / video making (like how to shoot a lively party with just 5 actors, or how to make it look like someone fell off a roof). I'd like to see separate forums for each of them, especially since I can answer the guerilla filmmaking questions and not the others!
You don't need separate ones - you can use the tags to separate out your favourites and those you never want to see (I use this on Arqade - I have a very small lost of tags I'm interested in and don't want to see any of the rest. And it works)
As to what questions are popular at a particular time - well, it's what is popular at that time