Official Google Reader Blog: New in Reader: a fresh design, and Google sharing →http://googlereader.blogspot.com/2011/10/new-in-reader-fresh-design-and-google.html
Google is bringing its new web app interface, the one you saw debut with Google+, to Reader. I was previously mistaken in thinking that Google is removing all sharing features save for Google+ with this redesign, but have thankfully been set straight by Hunt Henning.
To clarify: Google Reader still allows you to share articles to Twitter, Facebook, Instapaper, and more. What Google is specifically removing is the friending mechanism where you could follow other Google Reader users and view their shared stories inside of Google Reader.
Google has effectively stripped Google Reader back down to its essence as a feed reader and given it a new, arguably better designed interface. I’m down with that, though I still wish there was room for competition.