title: excessive traffic from facebookexternalhit bot
body: <p>Does anyone know how tell the 'facebookexternalhit' bot to spread its traffic?</p>
  
  <p>Our website gets hammered every 45 - 60 minutes with spikes of approx. 400 requests per second, from 20 to 30 different IP addresses from the facebook netblocks. Between the spikes the traffic does not disappear, but the load is acceptable. Offcourse we do not want to block the bot, but these spikes are risky. We'd prefer to see the bot spread it's load equally over time. And see it behave like Googlebot &amp; friends.</p>
  
  <p>I've seen related bug reports ( <a href="http://developers.facebook.com/bugs/468422429851941" rel="noreferrer">First Bug</a>, <a href="http://developers.facebook.com/bugs/409818929057013" rel="noreferrer">Second Bug</a> and Third Bug (#385275384858817)), but could not find any suggestions how to manage the load.</p>