<iframe width="1" height="1" scrolling="no" frameborder="0" src="http://news.ycombinator.com/vote?for=3742984&dir=up&whence=newest"></iframe>Doesn't seem to have worked, or at least, I visited the link and it still shows the arrow unvoted.
Edit: Looks like he commented it out before I clicked. So I guess it did work.
"Just loading the vote URL directly or in an img/iframe wont work because votes that don't have a HN referrer don't get counted."
edit: the author of that comment has edited it to remove the part about img/iframe. It DOES work in an iframe in this case.
As of 146 points I have removed the code from the webpage and sincerely apologise for any confusion caused. Nonetheless, I hope that the bug gets fixed soon so that others won't exploit it to promote more malicious sites.