title: What is meant by the rel="bookmark" link attribute?
body: <p>What is the purpose of the <code>rel="bookmark"</code> attribute in <code>&lt;a&gt;</code> tags? For example:</p>
  
  <pre><code>&lt;a href="http://stackoverflow.com/questions/ask" rel="bookmark"&gt;Click Here&lt;/a&gt;
  </code></pre>
  
  <p>Does it serve any SEO- or SEM-related purpose?</p>