The first impulse when facing a negative opinion about yourself is to challenge it. You will try to challenge the value of truth in that opinion. You will try to convince the other part that he’s wrong. Well, don’t do this. If there is a lesson to be learned from that, just learn it, but don’t engage in negative controversy. It will just add up to the power of that opinion.
One of the most effective techniques on building a powerful online presence is called “linkbaiting”. It’s a technique in which you gain popularity by talking bad about other people and waiting for them to respond. You don’t know anything about the other person, of course, but you’ll fake that and act like you do. In 95% of the cases, people will engage in negative controversy, regardless of the truth value involved. I think it’s almost a natural impulse of defending your own status. And that impulse is hijacked by others and that power redirected to their areas. Just don’t engage, learn what is to be learned and move on.