title: Amazon S3 Expiration Date?
body: <p>I hope this question isn't too rudimentary, but I'm confused...</p>
  
  <p>In the S3 documentation I read:</p>
  
  <blockquote>
    <p>All HTTP queries have an expiration
    parameter that allows you to set how
    long the query will be valid. For
    example, you can configure a web page
    graphic to expire after a very long
    period of time or a software download
    to only last for 24 hours.</p>
  </blockquote>
  
  <p>For a publicly accessible data object (file), does this mean that the data object (file) itself will not be valid anymore, or that the browser will simply re-cache the object after the expiration date.  As in, will I lose my data after ten years if I set my expirations that long?  Or if I set a download for 24 hours, is it gone/inaccessible past that?</p>
  
  <p>What if I don't set an expiration date?</p>