Defined as “reacting suddenly or without careful consideration of one’s words or actions,” is the most recent fault of too many tweeters who experience very serious consequences. Roseanne Barr (@therealroseanne), for example, recently published a racist tweet toward former Obama aide, Valerie Jarrett, resulting in ABC’s cancellation of Ms. Barr’s No. 1-rated TV show, her reruns scrapped and her dismissal from the talent …