Forum Traffic is not an issue, but you have to remember most of the traffic is people coming here to get something done. I tried getting more things incorporated into the forum a while back, such as Blogs, Guest tutorials from well known people etc, but like anything new here is gets pushed aside and never implemented.
As for the challenges and why they are failing is because they are to specific, rarely little open to Artist impression, Popular challenges will always be based upon a Generic theme and left to artist impression.
FOr example no disrespect to people involved the current challenge I believe is use a picture of a shoe and create art with it, this is so limiting to people, Where as if you had a challenge just simply named Big Cats and that is the only guideline you need, people can manipulate lion pictures with tigers, do a Digital painting or anything they want. I think challenges need to be given a title theme and that is it. As they develop people will get more and more involved, remove the hidden side to it, let people bounce of each other ideas use it to inspire yourself etc.
I suggest you only have 12 themes 1 for each month and repeat the themes each year.
so July can be Celebration, October can be Halloween December christmas etc and then the other months can be People, Wildlife, Landscape, Space etc......
