If you are mad as hell about a consumer experience you’ve had, you may want to exercise your right of free speech to express your dismay in a public forum - these days, by posting a negative review on a site like Yelp or Angie’s List. But a lawsuit in Virginia may make you think twice about how exactly to word your gripe to avoid provoking a defamation lawsuit that could cost you, whether you end up guilty of defamation or not. At a time when consumers routinely rely on what other consumers have to say about products and services, the case has bearing on the boundaries of online behavior.