The only thing that these people are saying, by accepting to rent their signature space, is that they need the money. Nothing else.
No, what they are saying is that they are willing to be paid to post.
The rest of us then have to try to determine if they are posting because they have a genuine passion for what they are saying or because they are trying to earn their money. Of course they will all say that it doesn't affect how often they post or the quality of their posts. But how are we to know?