Why we delete comments. (And how you can make us stop.) | The A.V. Club:

Past [comment] deletions have prompted charges of censorship. Let’s define some terms: If we attempted to pass a law preventing you from saying something terrible, that would be censorship. If you showed up in our living room attempting to say the same thing, we’d have the right to throw you out. The First Amendment forbids Congress from passing laws that abridge freedom of speech on a national level; it does not in any way apply to our right to delete posts on this site.

(via Derek)