title: What algorithm does google use to make Chrome browser's address bar to act as a default search bar for many websites?
body: <p>I am wondering what algorithm does google use to make chrome browser's address bar to act as a default search bar for many websites like SO, Quroa etc. but not for facebook, metastackoverflow etc..</p>
  
  <p>For example if you want to search for a topic in stackoverflow, you can do like this in chorme.</p>
  
  <p><img src="https://i.stack.imgur.com/HCsCB.jpg" alt="enter image description here"></p>
  
  <p>And the search results will directly take you to the stackoverflow page. i.e.</p>
  
  <p><img src="https://i.stack.imgur.com/ahIiC.jpg" alt="enter image description here"></p>
  
  <p>The same will happen if you choose to search <code>quora.com</code> also in chrome's address bar. But this won't happen if you search like <code>facebook.com</code> in the address bar and many other websites that have a search bar.</p>
  
  <p>How is this happening? What algorithm does google use to make this happen?</p>
  
  <p>Hope I am clear with my question? Any help would be appreciated.</p>