Social activism is an intentional action with the goal of bringing about social change. If you feel strongly about a cause and are working towards a change, you could be considered an activist. An activist is anyone who is fighting for change in society. An activist can be a student attending a rally against tuition increase, a politician fighting against international human rights abuses or a mother of a child killed by a drunk driver talking to students about drinking and driving. Social activists consider the larger picture – how can they find ways to end injustice and to create strong communities which encourage economic, social and psychological health. 
Social activism is about taking direct action to support a cause.