Is a positive book review an endorsement?

[Last week, book endorsements came up in a discussion thread on Goodreads, the best social media site for readers and writers. That little exchange motivated this blog post. Comments are always accepted.]

Product endorsements are as common as eyes on a potato. If you ever did any “live experiments” in grade school general science “labs,” you know those eyes can sprout. Mark Watney knows that a good dose of fertilizer helps, but the sprouts will come even in sugar water (maybe even tap water i...