Last week, in a Fairfax, Virginia courtroom, a jury announced it had determined a homeowner's Yelp "review" of a local general contractor was in fact old-fashioned slander. It started in 2011, when Jane Perez posted a review that alleged contractor Dietz Development LLC had not only performed shoddy and destructive work on her home without a license, but also that a member of Christopher Dietz's crew had stolen her jewelry. So Dietz sued for defamation, to the tune of $750,000 in damages, which he may have been awarded had he not responded on the social network with what the jury...