title: Why are callbacks more "tightly coupled" than promises?
body: <p>Can you explain me the following phrase (taken from <a href="https://stackoverflow.com/a/6824836/196210">an answer to Stack Overflow question <em>What are the differences between Deferred, Promise and Future in Javascript?</em></a>)?</p>
  
  <p>What are the pros of using <a href="http://en.wikipedia.org/wiki/JQuery" rel="nofollow noreferrer">jQuery</a> promises against using the previous jQuery callbacks?</p>
  
  <blockquote>
    <p>Rather than directly passing callbacks to functions, something which
    can lead to tightly coupled interfaces, using promises allows one to
    separate concerns for code that is synchronous or asynchronous.</p>
  </blockquote>