PPP dis-approved Science to Society

After more than half a year of the approval, payperpost (ppp) disapproves this blog. Blogs popularity has not been gone bad during this time. I don't claim that its popularity has increased either. So, question is why did they approve and why they dis-approved now? According to the email they sent, they say

"you may have heard that we're enforcing stricter controls for blogs submitted to the PayPerPost network".

That means its bot because of the blog, its because of the policy change of ppp. Is it the effect of economic recession? well, may be.

Pay per post provides you oppurtunities to write reviews as your blog post and this is payed. Although I didn't get large number of oppurtunities, some blogs earned lot of money, according to ppp website.