title: Custom tags... why not?
body: <p>I found a site with an guide to add custom tags to html, the same way people make ie work with the new HTML5 tags. I must admit I think it would be great to add my own tags, would make it easier to "scan" the the code, and find what you are looking for.
  But every site I found about it, people say it's not good.... but why isn't it good?</p>
  
  <p>Example html with class:</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;ul class="commentlist"&gt;
      &lt;li class="comment odd"&gt;
      &lt;div class="1"&gt;
          &lt;div class="avatar"&gt;
              &lt;img src="http://placehold.it/60x60" width="60" height="60" /&gt;
          &lt;/div&gt;
          &lt;div class="metadata"&gt;
              &lt;div class="name"&gt;Name&lt;/div&gt;
              &lt;p&gt;response1&lt;/p&gt;
          &lt;/div&gt;
      &lt;/div&gt;
      &lt;ul class="children"&gt;
          &lt;li class="comment even"&gt;
              &lt;div class="2"&gt;
                  &lt;div class="avatar"&gt;
                      &lt;img src="http://placehold.it/60x60" width="60" height="60" /&gt;
                  &lt;/div&gt;
                  &lt;div class="metadata"&gt;
                      &lt;div class="name"&gt;Name&lt;/div&gt;
                      &lt;p&gt;response1a&lt;/p&gt;
                  &lt;/div&gt;
              &lt;/div&gt;
          &lt;/li&gt;
          &lt;li class="comment odd"&gt;
              &lt;div class="3"&gt;
                  &lt;div class="avatar"&gt;
                      &lt;img src="http://placehold.it/60x60" width="60" height="60" /&gt;
                  &lt;/div&gt;
                  &lt;div class="metadata"&gt;
                      &lt;div class="name"&gt;Name&lt;/div&gt;
                      &lt;p&gt;response1b&lt;/p&gt;
                  &lt;/div&gt;
              &lt;/div&gt;
          &lt;/li&gt;
      &lt;/ul&gt;
  &lt;/li&gt;
  </code></pre>
  
  <p></p>
  
  <p>And here what I could do with custom tags, I think that would be much easier to find my way around, so why not:</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;clist&gt;
  &lt;ccommentbox class="odd"&gt;
      &lt;ccomment class="1"&gt;
          &lt;cavatar&gt;
              &lt;img src="http://placehold.it/60x60" width="60" height="60" /&gt;
          &lt;/cavatar&gt;
          &lt;cdata&gt;
              &lt;cname&gt;Name&lt;/cname&gt;
              &lt;ctext&gt;response1&lt;/ctext&gt;
          &lt;/cdata&gt;
      &lt;/ccomment&gt;
      &lt;cchildren&gt;
          &lt;ccommentbox class="even"&gt;
              &lt;ccomment class="2"&gt;
                  &lt;cavatar&gt;
                      &lt;img src="http://placehold.it/60x60" width="60" height="60" /&gt;
                  &lt;/cavatar&gt;
                  &lt;cdata&gt;
                      &lt;cname&gt;Name&lt;/cname&gt;
                      &lt;ctext&gt;response1a&lt;/ctext&gt;
                  &lt;/cdata&gt;
              &lt;/ccomment&gt;
          &lt;/ccommentbox&gt;
          &lt;ccommentbox class="odd"&gt;
              &lt;ccomment class="3"&gt;
                  &lt;cavatar&gt;
                      &lt;img src="http://placehold.it/60x60" width="60" height="60" /&gt;
                  &lt;/cavatar&gt;
                  &lt;cdata&gt;
                      &lt;cname&gt;Name&lt;/cname&gt;
                      &lt;ctext&gt;response1b&lt;/ctext&gt;
                  &lt;/cdata&gt;
              &lt;/ccomment&gt;
          &lt;/ccommentbox&gt;
      &lt;/cchildren&gt;
  &lt;/ccommentbox&gt;
  </code></pre>
  
  <p></p>