As far as of now Yobit is working very well within the rules of the forum. The problem is actually being created by spam users like the one you have shown( although I think he will soon be banned as he is violating Yobit Guidelines). To stop this yobit should limit up the number of participants they are willing to accept in their campaign and only then they would be able to regulate spam content although that being said test checking 140 posts per participant in a week to ensure that its a contributing reply seems like an impossible task for any human manager. But this is for the second time by yobit so they must have thought of this before launching this campaign. Let's wait how it turns out.