In the Goodreads metadata plugin it states the following
"# Unlike the other metadata sources, if we have a goodreads id then we
# do not need to fire a "search" at Goodreads.com. Instead we will be
# able to go straight to the URL for that book."
If the plugin is able to extract a goodreads id it goes straight to:
http://www.goodreads.com/book/show/%ID%
This URL works fine.
The plugin itself appears to be unused though - if I add logging statements to it, they do not show up in the logfile - not sure what's going on here. The plugin is definitely loaded by calibre as I made a couple of typos with my edits, and they DID show in the log as errors.