LONDON — Rudeness and throwing insults are cutting online friendships short, with a survey yesterday showing that people are getting ruder on social media and that 2 in 5 users have ended contact after a virtual altercation.

As social-media use surges, the survey found that so has incivility, with 78 percent of 2,698 people reporting a spike in rudeness. The survey was conducted by the corporate-training firm VitalSmarts.