title: how to determine if webpage has been modified
body: <p>I have snapshots of multiple webpages taken at 2 times. What is a reliable method to determine which webpages have been modified? </p>
  
  <p>I can't rely on something like an RSS feed, and I need to ignore minor noise like date text.</p>
  
  <p>Ideally I am looking for a Python solution, but an intuitive algorithm would also be great.</p>
  
  <p>Thanks!</p>