I use several different webmaster forums to buy, sell & trade from links to buying domains & websites to finding coders & designers.
That would be my idea of increasing traffic & members.
A money making idea from this would be to have a premium option when posting to make it more visible something cheap but not too cheap that everyone would use it and the perk was lost.
This idea may get shot down in a ball of flames but I do spend money and time in other places using these services that webmasterworld would be able to handle. then we have the problem that no one will leave...