probably why the link to their site is "rel=nofollowed" this make the link, just a link - and if their goal is anything but "sharing information" (I.e. ranking in google..) this does nothing for him.
'nofollow' does not make outlinks useless. Some crawlers still follow them. Some users still click them (and thus toolbars/etc report the visits). Some secondary inlinks may be created by people who discovered an article via a nofollow outlink.
And even Google may count them for something -- I'm sure 'nofollow' is part of their analysis, but I doubt it's equivalent to 'the link wasn't even there'. That'd be throwing away information, and Google didn't get where they are by throwing away bits. (I would guess the 'nofollow' discount varies by site.)
He's running ads on his site and these submissions are driving traffic to them. He's not increasing his PageRank, but it's not true that these submissions are doing nothing.
http://news.ycombinator.com/item?id=392861