Well, at least for books on your " to read" shelf. You can opt out and you can select which retailers. "Opt out" versus "opt-in" -- even for features I really want -- always offends me. Feel free to reblog.
See the announcement thread in a group less than 5% of goodreads members belong to for directions on opting out or customizing: https://www.goodreads.com/topic/show/18114746-goodreads-deals-u-s-members?page=1#comment_number_1
I suppose it could be worse (for example if only listing Amazon deals) but cynical me thinks it's a way for Amazon to send countdown deals and other promotions for authors out to goodreads members.