<a rel="value">
<a rel="alternate">Print page, translated, mirror, etc.</a>
<a rel="author">creator credit</a>
<a rel="bookmark">permanent url</a>
<a rel="external">link to different site</a>
<a rel="help">more info</a>
<a rel="license">info</a>
<a rel="next">series</a>
<a rel="nofollow">unendorsed, used by Google. Google won't follow</a>
<a rel="noopener">no context passed</a>
<a rel="noreferrer">won't know where they came from</a>
<a rel="prev">series</a>
<a rel="search"></a>
<a rel="tag">keyword, taxonomy, etc.</a>
