All the Amazon haters! Pity poor Amazon! They need your sympathy! sheesh
More seriously, an alternative to Goodreads with ads would be fine as long as user contributions could not be sold. I think people would go for it. There are highly successful community sites that are ad-driven. As long as the ads are not to intrusive, people deal with it. The understand the site has to be paid for.
The Amazon-eats-Goodreads (and the rest of the world to follow) debacle offers an excellent opportunity for someone with the knowledge and time to set up an quick alternative and invite people over. It only needs a basic site to begin with with development to follow. Ultimately this is the way to defeat the big competition-eating organizations like Amazon. It's cat and mouse. Add the caveat that no user contributions can be sold, and we may ultimately have an Amazon killer.