The ability to publish your opinions to the entire world instantly is a powerful thing. It can be very liberating, but can pose significant legal risks at the same time - especially when you are giving an opinion about specific person or business. It has never been easier to defame someone, which could lead to significant legal liability for social media users who aren't responsible.
Be sure to check out the most recent edition of Network Magazine, where my article entitled When in Doubt, Don't Tweet It Out is featured.