title: HTML5: Why not use my own arbitrary tag names?
body: <p>As far as I know, it is perfectly legal to make up tag names in HTML5, and they work like normal with CSS styling and nesting and all.</p>
  
  <p>Of course my arbitrary tag names will make no difference to the browser, which does not understand them, but it goes very far in making my code more readable, which makes it easier to maintain.</p>
  
  <p>So why should I NOT use arbitrary tag names on my pages?  Will it affect SEO?  Will it break anything?</p>
  
  <p>IMPORTANT EDIT: Older browsers DO NOT choke on unsupported tags when used with <a href="http://ejohn.org/blog/html5-shiv/">http://ejohn.org/blog/html5-shiv/</a></p>