Our recent both investor / admin Juby give me this idea to create a new group "Hyip admins" who could propose their programs to be advertised. Then members vote Yes or No to accept or not advertising banners of program proposed. The proposition could contain the lifetime of advertising. In a way, members decides what banners ads are allowed in the forum. If the proposition is rejected by community, this one is deleted. The admin can always make a new proposition with a new program or the same program with a different lifetime.
The big advantage is a member can't complain about a program advertised because the community has voted in majority for the program. Moreover, we get some money added to our pool which help also active members to recover some of their losses.