anchor.diff:          <div class="col-sm-3">
             <div class="thumbnail">
               <a href="19911206000000/http://slacvm.slac.stanford.edu/FIND/default.html">
  -               <img alt="SLAC first webpage" src="/images/featured_sites/slac_1991.jpg">
  +               <img alt="SLAC first web page" src="/images/featured_sites/slac_1991.jpg">
                 <div class="caption">
  -                <h3>SLAC first webpage</h3>
  +                <h3>SLAC first web page</h3>
                 </div>
               </a>
             </div>
  
positive.code:         <div class="col-sm-3">
            <div class="thumbnail">
              <a href="*/http://www.slac.stanford.edu/">
                <img alt="SLAC homepage 1995-1998 Timemap" src="/images/featured_sites/slac_1996.jpg">
                <div class="caption">
                  <h3>SLAC homepage 1995-1999</h3>
                </div>
              </a>
            </div>
  
negative.code:         <div class="col-sm-3">
            <div class="thumbnail">
              <a href="19990104000000/http://www.slac.stanford.edu/">
                <img alt="SLAC home page 1999" src="/images/featured_sites/slac_1999.jpg">
                <div class="caption">
                  <h3>SLAC home page 1999</h3>
                </div>
              </a>
            </div>
  