In a survey conducted by corporate training firm VitalSmarts, 78-percent of Facebook users said they've noticed a trend in friends being less polite online than they are in real life. Two in five users say that they've un-friended someone on social media after getting into an argument in cyberspace. Lack of virtual manners seems to be surging as social media becomes more common, with 67-percent of U.S. adults now using Facebook. But while a friend might be rude virtually, most don't let that affect how they interact with that person when they meet face-to-face. Only one in five said they had avoided contact with someone they knew in real life after an unpleasant run-in on the web.