Ask YC: negative comments disappear..?

The more negative the vote on a comment, the more it fades into the page background. The reverse is also true. Posts with 1 point are not quite black. 2 and higher points are in fact in black print.

This is the first time I've seen a post entirely disappear though.

If you look at the source, that comment has no text, just about a zillion <p> tags. There are more comments below it.

He could have deleted it on his own because it was unpopular maybe?