Topic 5568262
If you go far back in their spreadsheet there was even users making 115 posts per week, all 115 of those posts in the gambling section. Their ‘best posters’ seem to be chosen at random, since it's usually a new set of posters each week, many of them being some of the worst spammers on the forum.
I just saw this and it was really surprising. They pay for posts that aren't even limited per week. This makes every participant feel like they're in a race to make as many posts as possible and earn more money than others. 
I know not all participants registered in the campaign are like that. Now they set a maximum post limit for each participant based on the weekly rating. But the maximum post limit is still quite high, between 50-70 posts per week.