title: Which is most used? RSS or Atom? and which one is better to build from?
body: <p>I am thinking of using either RSS or Atom in my project, but also "enhancing" the feed with some of my own special attributes specifically used by my project.</p>
  
  <p>So I have two questions:</p>
  
  <p>1) Which is most used of RSS and Atom on the web and by the big sites?</p>
  
  <p>2) Which is most suitable to be build from by adding my own tags?</p>
  
  <p>Update:</p>
  
  <blockquote>
    <p><em>So RSS is most used, but I should pick Atom since I need to make my own tweaks on a feed? If RSS is more popular, why not pick that? Why didn't Google pick that?</em></p>
  </blockquote>