Definition of Rich Snippets

Snippets are a few lines that appear as the description of a web page appears in search results. Snippets is generally taken by Google from the content of the page, if we use the meta description, it is likely Google will also use the meta description that we use.
Rich snippets are designed to summarize the content of a page in a way that makes it even Easier for users to understand what the page is about in our search results. If you're considering taking advantage of rich snippets, think about Whether a user would find the information helpful when choosing between search results.
By Rich Snippets, more data can be displayed in a snippet that appears in Google search results, for example, show user ratings, price for a product, and other data that support. So Rich Snippet created as a summary of the contents of a page in markup structure to let users better understand a search result in Google before visiting the pages that appear in search results. By Rich Snippets, website owners are expected to provide a summary and unstructured data with better search engines on a page.

Rich snippets allow webmasters to help us provide even better summaries of data using structured markup that they can add to their pages.

Markup format that can be used to create rich snippets is Microdata, Microformats and RDFa. In addition, there is another format that is gaining in popularity is schema.org used as a collaboration from Google, Microsoft, and Yahoo!.

schema.org is a collaboration by Google, Microsoft, and Yahoo! to improve the web by creating structured data is a markup schema supported by major search engines. On-page markup helps search engines understand the information on webpages and provide richer results. A shared markup vocabulary makes it Easier for webmasters to decide on a markup schema and get the maximum benefit for their Efforts

In the meantime I've tried to use that Schema.Org this blog, in addition to easy to apply to our website, complete documentation in Schema.Org well. Here is an example of the use of simple Schema to page article:

Structure before using Schema page:
<div class = "post"
<h1> Article Title </h1>
<div class="date"> In Posts on December 10 April, 2013, By blogger </div>
<div class="contents">
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Aliquam a closely gravida tincidunt aliquet eros. Aliquam closely volutpat. Nunc Mauris sit amet luctus a sollicitudin vel eros vitae justo. Aenean ultrices feugiat est, in scelerisque non fermentum odio. Nam at magna neque. Vestibulum libero nisi, blandit in dictum vel, malesuada at sem. Vestibule closely quis dictum Mattis et Tellus. Nulla facilisi. Quisque Arcu Lacus, sagittis in interdum vel, condimentum a tortor. Aenean tempor laoreet tincidunt augue vitae. In faucibus closely Pretium Pretium sed ipsum Nunc aliquam porta. Mauris Lacinia Tellus at commodo placerat. Sed tincidunt urna dolor.
</div>
<div> 19 Comments to "Article Title" </ div>
</div>

Structure page after using Schema:

<div class="posts" itemscope itemtype="http://schema.org/Article">
<h1 itemprop="name"> Article Title </ h1>
<div class="date"> In Posts on April 10 <span itemprop="datePublished" content="2013-04-10"> <span> April 2013, By <span itemprop="author"> <a href = " https://plus.google.com/id?rel=author "itemprop =" url "> blogger </ a> </ span> </ div>
<div class="isi" itemprop="articleBody">
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Aliquam a closely gravida tincidunt aliquet eros. Aliquam closely volutpat. Nunc Mauris sit amet luctus a sollicitudin vel eros vitae justo. Aenean ultrices feugiat est, in scelerisque non fermentum odio. Nam at magna neque. Vestibulum libero nisi, blandit in dictum vel, malesuada at sem. Vestibule closely quis dictum Mattis et Tellus. Nulla facilisi. Quisque Arcu Lacus, sagittis in interdum vel, condimentum a tortor. Aenean tempor laoreet tincidunt augue vitae. In faucibus closely Pretium Pretium sed ipsum Nunc aliquam porta. Mauris Lacinia Tellus at commodo placerat. Sed tincidunt urna dolor.
</div>
<span <div> itemprop="interactionCount" content="UserComments:19"> 19 </ span> Comments on "Article Title" </ div>
</div>
To determine whether the rich snippets we have applied correctly, can use the data structured testing tool. It took a few days for Google start displaying the data structures that we've created. We could have checked in webmaster tools on the Optimization - Structured Data.