title: Semantic markup: Why <header> instead of <div id="header">?
body: <p>Okay, so I understand the hype about semantic markup: it enhances/ further specifies the meaning of an element or page for search engines, and therefore for humans reading search results. All credits to microformats and <code>&lt;h1&gt;, &lt;h2&gt;, &lt;p&gt;</code> and such, because these tags indicate a hierarchical structure and/or specific purpose and add meaning to the page. </p>
  
  <p>But why are there now tags like <code>&lt;aside&gt;, &lt;header&gt;, &lt;footer&gt;</code>? What is their advantage over <code>&lt;div id="aside/header/footer"&gt;</code>? </p>
  
  <p>These tags have no specific sub-properties or attributes like an <code>&lt;audio&gt;, &lt;form&gt;, &lt;img&gt;</code> tag (src, action, etc.) and I can hardly imagine it means such an improvement for search engine performance to look for a header tag instead of a header id. Furthermore, if beginners make mistakes while using these tags, wouldn't it be even worse because the error goes all the way down to the DOM node level?</p>
  
  <p><strong>So why are there new HTML 'semantic' tags with no apparent benefit over the plain ol' divs? Or if this is wrong, what IS the benefit?</strong></p>
  
  <p><strong>EDIT:</strong> The answer I was looking for is in the link Anthony pointed at in the 4th comment of this thread: <a href="http://www.w3.org/TR/html5/sections.html" rel="noreferrer">http://www.w3.org/TR/html5/sections.html</a>. </p>
  
  <p>The justification for the existence of tags like <code>&lt;aside&gt;, &lt;header&gt;, &lt;footer&gt;</code>, is: </p>
  
  <blockquote>
    <p>Sectioning content is content that defines the scope of headings and footers. - W3C</p>
  </blockquote>