Frankly I find the posts from authors and publishers on GR annoying. THey see GR as a place to market their books and sell them. Of course Amazon's entry is going to polarize them along existing camps.
That said, from a community angle I think there's a tremendous problem that is being ignored by all these industry bloggers. I've been following the community responses at the main blog (http://www.goodreads.com/blog/show/413-exciting-news-about-goodreads-we-re-joining-the-amazon-family) and in a few general GR communities for a few days, and I think that the management /response back to the community by Goodreadshas been slow and flat-footed.
Reading through the first 800 comments is pretty telling. (I have to catch up on the next 1200.)
For the cataloguers -it was not all that long ago that Amazon was perceived as an unsympathetic figure to the community thanks to the mess over the book API. I feel bad for the volunteer librarians who worked hard to help their community transition to Ingram's data when something went bizarrely wrong b/w Goodreads /Amazon: http://readwrite.com/2012/01/30/why_goodreads_gave_up_on_amazon . THe blog post tone could seem somewhat dismissive of their previous efforts and kind of like a slap in the face. I definitely get that sense and think GR needs to smooth things over with the librarian /cataloguing community.
As far as the reviewers -- Amazon and Goodreads are considered very different review environments with Amazon as the more restrictive of the two. There are legitimate concerns about what will happen to reviews for books borrowed (not purchased) or written by writers for other writers.
While authors may embrace the potential cross-over of reviews, the book bloggers on GR are a pretty independent sort. The idea that their work might be subsumed into Amazon without opt-out concerns them. Thgat it might be used to drive book sales on Amazon also irks them. (And this perception isn't helped by changes to the settings that happened after the announcement that placed Amazon as the first "buy" button on books vs. Kobo/B&N which used to hold that top spot.)
And then the data mining -- well, I guess some people are now aware that they represent a bunch of data to improve Amazon's algorithms, review banks, or sales. Of course that isn't going to sit well with a community who thought they were building something around a shared love for books.
But the biggest mistake any community manager can make is making changes particularly as big as this one without talking it through with the community itself.
I just watched people rage on Wattpad over changing "fans" to "followers"... something as big as "getting a new owner" can't possibly be met calmly by people who invest hours of their lives into a social network.
Of course, I doubt anyone in the publishing world is going to get this at all... and that's the sad part about the internet. Communities are generally never safe from becoming a sales point.... it's almost a joke how if anything gets big enough it'll inevitably be sold off as a source of data for some bigger fish to fry.
So glad I never invested in GR as a sole place for posting reviews or used it to catalog my books. I'd be pretty pissed too.