<section>: The Generic Section element

<section> is a generic sectioning element, and should only be used if there isn't a more specific element to represent it. Each <section> should be identified, typically by including a heading (<h1>-<h6> element) as a child of the <section> element, wherever possible.

Example

<section>
  <h2>Heading</h2>
  <p>Bunch of awesome content</p>
</section>

<article>: The Article Contents element

The <article> element represents a self-contained composition in a document, page, application, or site, which is intend to be independently distributable or reusable(e.g., in syndication).

Usage notes

• Each <article> should be identified, typically by including a heading (<h1>-<h6> element) as a child of the <article> element.
• When an <article> element is nested, the inner element represents an article related to the outer element. For example, the comments of a blog post can be <article> elements nested in the <article> representing the blog post.
• Author information of an <article> element can be provided through the <address> element, but it doesn't apply to nested <article> elements.
• The publication date and time of an <article> element can be described using the datetime attribute of a <time> element.

Example

<article class="film_review">
  <h2>Jurassic Park</h2>
  <section class="main_review">
    <h3>Review</h3>
    <p>Dinos were great!</p>
  </section>
  <section class="user_reviews">
    <h3>User reviews</h3>
    <article class="user_review">
      <h4>Too scary!</h4>
      <p>Way too scary for me.</p>
      <footer>
        <p>
          Posted on
          <time datetime="2015-05-16 19:00">May 16</time>
          by Lisa.
        </p>
      </footer>
    </article>
    <article class="user_review">
      <h4>Love the dinos!</h4>
      <p>I agree, dinos are my favorite.</p>
      <footer>
        <p>
          Posted on
          <time datetime="2015-05-17 19:00">May 17</time>
          by Tom.
        </p>
      </footer>
    </article>
  </section>
  <footer>
    <p>
      Posted on
      <time datetime="2015-05-15 19:00">May 15</time>
      by Staff.
    </p>
  </footer>
</article>