The first answer is to oppose such a move: it is against the freedom of expression. On the other side, the reality you might encounter on websites or forums is an increasing wave of hate, antisemitism and intolerance, giving the impression that we are living in the world untouched by the apparently evolutive process of civilisation. Most probably, people disputing or arguing on the net will not hesitate to kill each other, if face to face.
But, there are other tools to limit the intellectual pollution represented by dialogues written under the cover of anonimity, for example by instituting filter - programs blocking from publishing comments containing offensive words. And, creating, in parallel, educative programs aiming to help the return of humans to humanity - in schools, in the media, in the universities.
