on The Book Designer:
Two years ago, it was so easy to find the top Amazon.com reviewers and approach them and ask for reviews. There was software that let authors and publishers find the name and email addresses of the thousands of Amazon reviewers who had already written reviews of books in a similar vein.
Then, for some reason, in March of 2018, Amazon made a decision to hide the email addresses of reviewers on their profiles. Speculation was they did this because of the new GDPR rules and regulations but no one really knows why. This completely stopped authors from being able to email potential reviewers–even if the reviewers didn’t mind being contacted with their information public on their profile.
Does this mean it’s the end of finding targeted reviewers for books? Absolutely NOT! But it is a lot harder than it used to be.