This is nothing new. Amazon has always shared this information (and it tells you that it is doing so before you subscribe to a magazine/newspaper). In the quoted article, they're saying that Amazon shares more
compared to Apple.
Apple has flat out refused to allow magazine/newspaper publishers to have any details of who subscribes to their publications.
This restricts what those publishers can do in terms of content offered outside of the specific platform that the user is subscribing on (e.g. if the newspaper wants to let you access their web site as well as the digital version of the publication).
The reason Apple does not want to share the information is that it makes it much harder for the publishers to leave the closed ecosystem that Apple provides. They can't just contact all of their customers and say "we're leaving the App Store, find us in these alternate places".
For more see:
http://www.amazon.com/gp/help/custom...r=1-2#security