title: How does MongoDB order their docs in one collection?
body: <p>In my <em>User</em> collection, MongoDB usually orders each new doc in the same order I create them: the last one created is the last one in the collection. But I have detected another collection where the last one I created has the 6 position between 27 docs. </p>
  
  <p>Why is that?</p>
  
  <p>Which order follows each doc in MongoDB collection?</p>