title: Inject advertisements in pages
body: <p>Today I noticed that in the Chrome web store dashboard, under my extension's settings there is a check-box labeled "Ads Behavior", and whose description is "This extension injects ads into some third-party websites.".</p>
  
  <p>My questions are:</p>
  
  <ul>
  <li>Can an ad-supported extension inject advertisements in a page visited by the user?</li>
  <li>If so, what is an acceptable policy?</li>
  <li>Can the extension replace existing advertisements (even though that seems to me kind of unethical/stealing) or must it only create new ones?</li>
  <li>Is it possible to use any ads network or must it be adsense?</li>
  </ul>
  
  <p>Thanks</p>