Social DRM epub

I was looking into netgalley catalogs today (as one regularly does =P) and came across this on one of my approved titles:

Social DRM Epub? What is that?

So, I downloaded the book and saw the following on the first page:

There is also a last page that reminds you to leave feedback on netgalley about the book.

 

I did a little bit of research and saw that netgalley added this feature last year; it just happened that I never came across it before.

"With Social DRM, member information is publicly and privately embedded within the file, so that illegal sharing can be tracked if needed. Readers can read on any platform that supports ePub or PDF files, and move content between devices. The cost of Social DRM downloads will be included in the NetGalley subscription price, and publishers & authors will continue to have full control over security and reading options across their account or title-by-title."

src:http://www.digitalbookworld.com/2015/netgalley-adds-social-drm-reading-option/

So, basically this is another way of watermarking a book in order to be able to trace the original owner. I think this is a neat addition and much less intrusive than the usual DRM watermark that doesn't let me even view the book with calibre.

 

What are your thoughts on this? Have you noticed this different format before?