Works really good at turning lies into accepted facts.  I've had multiple journalists who printed outright falsehoods that I complained to point to some (usually reddit) thread and say "no one disagreed" --  though on reddit it's extra sweet since logged out users don't see neg rated comments, so in one instance I'd actually thoroughly debunked the post.

In any case, I don't mean to argue that anyone needs to waste their time on idiots.  But ignore isn't a magic fix-all solution either and has in its own way cause a tremendous amount of harm, but sure it saves the poster from wasting their time.

It occurs to me that keeping a counter on what percentage of posters in the thread are ignoring a poster could help, but that's getting offtopic.