title: How do you test the performance of your website from multiple locations world-wide?
body: <p>Following on from <a href="https://stackoverflow.com/questions/53738/how-do-you-test-the-performance-of-a-website">How do you test the performance of a website?</a> :</p>
  
  <p>What tools/sites/services do you use to find out the performance of your website from multiple locations around the world?  </p>
  
  <p>There are always complaints that sites are slow under certain circumstances (especially from physically-distant places), and it would be nice to be able to tell where it is particularly slow from.</p>