From Bruce Hood’s book The Self Illusion, this is a dynamic I’ve certainly seen occur online:

As soon as we blend into the crowd, we no longer feel the need to put in as much effort if it is not recognized. It is only if the group appreciates our efforts that we try harder. This need for recognition also explains why groups can become more polarized on issues that would normally generate only moderate views. In an effort to gain group approval, individuals adopt increasingly extreme positions that they feel represent the group, which in turn drags the group further toward that position. If you couple that dynamic force with “groupthink,” the tendency to suspend critical thinking when we are one of many decision-makers so as to try and galvanize the gathering, then it is easy to see how we behave so differently in groups than we would as individuals.