I think he means the quotes praising the book that appear typically on the back cover of a physical book. https://susanleighnoble.wordpress.com/2012/09/18/writing-an-...
I think they may refer to the actual Amazon page, found under "Editorial Reviews". For example, from a random book I found.
https://www.amazon.com/gp/product/0385542364/ref=s9_qpp_gw_d...
Editorial reviews by Oprah, someone from the NYT, People, NPR etc.
What does this mean? Is it a typo for blogged, a new social network used by Knuth and Shteyngart, or a word I've never heard of?