<blockquote>
  <p>The only two possible positive things voting now provides are:</p>
</blockquote>

<p>What about when you're searching for something, and you get several results - don't you look to the highest-voted matches first? I do. Even if the choices are 0 and -1, all else being equal I'll look at the 0-ranked question first. In that scenario, even the down-vote led to a positive result: helping me to narrow down search results.</p>

<h3>See:</h3>

<ul>
<li><a href="http://meta.stackexchange.com/questions/139/why-should-i-upvote-a-question">Why should I upvote a question?</a></li>
<li><a href="http://meta.stackexchange.com/questions/1871/what-purpose-does-downvoting-questions-serve">What purpose does downvoting questions serve?</a></li>
</ul>