Annie, I really didn’t research that in detail, because this was already running long for a PJ piece. Looking at the Distribution Agreement, it doesn’t look awful — if you are self-publishing via Kindle, you get a 35 percent royalty, they pay 60 days after the sale, both sides can revoke the agreement but Amazon gets to keep an archived copy so they can re-supply a book that someone has purchased. Publishing looks to be simple — upload the book in HTML, with a few custom tags for Kindle specifics, or convert it for Mobibooks, or upload Word or PDF. (Some of the things I might publish would have heavy equations, and I don’t see yet how they handle that.)
Now, I Am Not A Lawyer, this Should Not Be Taken as Legal Advice, etc., and I can see an argument that charging 65 cents on the dollar for formatting and sending it out might seem kind of high — on the other hand, it’s essentially no cost to do it, and you get a potential audience and a better cover-price royalty than you’d get from a printed-brick publisher.
