I was happily upvoting adam's new account, and then remembered that this is hacker news:

    var links = document.getElementsByTagName('a'); for (var i = links.length >>> 0; i--;) {if (links[i].innerHTML==='adamwhitcroft'){var j=i; while (!links[++j].id){}; console.log(links[j], links[j].click())}}

If you paste this into WebKit inspector and run it, it will click all of adam's upvote links.

Here's a little puzzle - there is one trivial change that will change upvotes to downvotes. Can you guess what it is?