I'm thinking of the efficacy of slacktivism, i.e. promoting an opinion via social media. When people get rile up about something, it isn't one thoughtful person making a case for it, it is 100s of people making emotional cases for it over and over. It is the irl version of surround one person with a few hundred people standing around shouting.
Is this good or bad? It cuts both ways. It makes it harder to change minds in either direction on any issue.