I'll be affected, but hope I wasn't a target.
I think it's more in response to some fo the sites that do freebies only. Amazon had already taken them down a notch in earnings (due to high volumes and low conversions, they got moved to the "deals site" categories). so, they just started charging authors to promote their free books and continued on.
I take no advertising or paid placement from authors or publishers (I have ads from Adsense, yes, to cover costs, plus disclosed affiliate income - none from B&N as they simply stopped paying on ebooks months ago).
Amazon has set a rather low and arbitray limit on ebooks. Many fair bloggers with a fair following won't be mentioning any free books, as one or two might bump them over for the month. None of us have any idea how many our referrals currently buy, as there are still no reports for us to use to get the numbers. Also, any free books you buy count, even if we referred you to Amazon only from links to $$ books and "just leaving off the tag" doesn't help, either (the last affiliate site you clicked thru gets those free books added to their total).
We knew this was coming and have prepared for the changes. There is no way that smaller deal pages and blogs can generate enough paid Kindle sales to offset the freebie downloads so on the Kindle side of The Cheap we announced today that we will no longer feature or offer links to free Kindle books. We are hopeful that Amazon will take into account the wording they mentioned in the email yesterday about "primarily promoting free e-books". Not something we have ever done at The Cheap but we did end up promoting more as KDP opened up the floodgates on free books. I am excited to go back to our roots of offering "cheap" e-reads. We just started an extremely affordable advertising program last July, at the urging of our author friends, and it has been a wonderful success. Prior to that program becoming available we offered indie authors free promotion continually. We still do.
It appears that some people have started offering/selling scripts for "unlimited posts" of free products at Amazon, much as they did to post to Pinterest for a while (until Pinterest simply shut down all affiliate tags to Amazon). These may have tipped the scales (more than the smaller blogs that actually worked to find what they posted; those that just used the api to list all "newly free" books had already been whacked on the head and forced to reduce their free book postings or were moved to a much lower payment tier schedule, along with deals sites).
Authors were gaming the ratings using a combination of KDP and paid placement at free sites, also, so I suspect they want to lower that. Delivery of free books costs them close to nothing (most everyone uses wifi now, I suspect, with many fewer using 3g for delivery, and many never download their free books, just "send them to the cloud" in the first place).