He is incentivizing each post by paying for it. OF COURSE every single person will pad their post count.
Then you have signatures like mine which pay per month, not per post.
Bitpop
What campaign are your referring to as its not in the main thread for sig-ad campaigns
https://bitcointalksearch.org/topic/overview-of-signature-ad-campaigns-333916
I do agree that it does promote padding but really obvious spam and abuse of the system will likely just result in the campaign being closed to new participants then flushed clean, or a lot of hammer bashing over the holidays he-he.