Social media sites have made it possible for us to instantly share our thoughts with millions of people, but this also leaves a lot of room for people to say something that they might regret later.

According to a study to mark Holocaust Memorial Day, one in four people have regretted posting something on sites like Twitter and Facebook, mainly because it was inappropriate or upset someone.

Around 40 per cent of the 2000 polled said they used social media to speak up on an issue they felt passionate about.

Almost half believed that what they said had made a difference but more than a quarter of people surveyed admitted they would say, or have said, something on a site they would never say to someone's face.

A third of respondents had also witnessed or been a victim of online bullying.

"The rapid increase in the availability and use of social media has brought with it many positives and, as our research has revealed, one of these is the ability to speak up for things we are passionate about," the Daily Mail quoted Professor Robin Dunbar, Professor of Evolutionary Anthropology, Fellow of Magdalen College, Oxford as saying.

"However, it is important to remember that it is through experience in face-to-face interactions that we learn many of the social skills needed to navigate our way through our complex social world," he said.

Professor Dunbar had analysed the findings of this survey.

"Our research has shown that people are more prone to saying something on social media that they later regret, because in these digital environments we don't receive the immediate checks and balances that we get during face-to-face interactions," he said.

"This can therefore result in a careless or inappropriate tweet, or at worst, cyber bullying," he added. (ANI)