What is Microdata

About microdata

The HTML5 microdata specification is a way to label content to describe a specific type of information—for example, reviews, person information, or events. Each information type describes a specific type of item, such as a person, and event, or a review. For example, an event has the properties venue, starting time, name, and category.

Microdata uses simple attributes in HTML tags (often <span> or <div>) to assign brief and descriptive names to items and properties. Here's an example of a short HTML block showing basic contact information for Bob Smith.

<div> 
  My name is Bob Smith but people call me Smithy. Here is my home page:
  <a href="http://www.example.com">www.example.com</a>
  I live in Albuquerque, NM and work as an engineer at ACME Corp.
</div>

Here is the same HTML marked up with microdata.

<div itemscope itemtype="http://data-vocabulary.org/Person"> 
  My name is <span itemprop="name">Bob Smith</span> 
  but people call me <span itemprop="nickname">Smithy</span>. 
  Here is my home page:
  <a href="http://www.example.com" itemprop="url">www.example.com</a>
  I live in Albuquerque, NM and work as an <span itemprop="title">engineer</span>
  at <span itemprop="affiliation">ACME Corp</span>.
</div>

Here's how this sample works.

• In the first line, itemscope indicates that the content in the <div> is an item.itemtype="http://data-vocabulary.org/Person indicates that the item is a Person.
• Each property of the Person item is identified with the itemprop attribute. For example,itemprop="name" describes the person's name.

Nested entities

The example above shows contact information about Bob Smith, but it doesn't include his address. The example below shows the same HTML, but in this case, it includes the address property.

<div itemscope itemtype="http://data-vocabulary.org/Person">
   My name is <span itemprop="name">Bob Smith</span>, 
   but people call me <span itemprop="nickname">Smithy</span>.
   Here is my homepage: 
   <a href="http://www.example.com" itemprop="url">www.example.com</a>.
   I live in 
   <span itemprop="address" itemscope
      itemtype="http://data-vocabulary.org/Address">
      <span itemprop="locality">Albuquerque</span>, 
      <span itemprop="region">NM</span> 
   </span>
   and work as an <span itemprop="title">engineer</span>
   at <span itemprop="affiliation">ACME Corp</span>.
</div>

Here's how this sample works:

• The address property is itself an item, containing its own set of properties. This is indicated by putting the itemscope attribute on the item that declares the address property, and using the itemtypeattribute to specify the type of item being described, like this: <span itemprop="address" itemscope itemtype="http://data-vocabulary.org/Address">.

For more examples, see Nested items.

Date and time information

To specify dates and times unambiguously, use the time element with the datetime attribute. Here, thestartDate property indicates the start date of an event. The value in the datetime attribute is specified using the ISO date format. Using this format lets you provide search engines with detailed date, time and—optionally—time zone in ISO format ("2009-10-15T19:00-08:00"), while still displaying the date on your page in a user-friendly way ("15 October 2009, 7PM").

<time itemprop="startDate" datetime="2009-10-15T19:00-08:00">15 October 2009, 7PM</time>

Source:-http://support.google.com/webmasters/bin/answer.py?hl=en&answer=176035 

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What Is Original-Source?

The original-source meta tag can be used by publishers wanting to claim their article as the original version. In a sense, it’s somewhat like the rel=”canonical” tag, which can be used to indicate the canonical version of similar web pages (more about the canonical tag below).

Search Engine Land, for example, could use the original-source meta tag on this article (and others) to indicate that ours — not the various sites that scrape our content or reference it in other ways — is the original version.

Similarly, Google says this meta tag can also be used in the same way publishers link to other sites. For example, since this article is also referencing an announcement on the Google News blog, we could use the original-source tag similarly to how we cite them via a link.

In fact, Google says you can cite several different sources with multiple versions of this tag if you want to credit each one that led to the article you’ve published. The tag looks like this:

meta name=”original-source” content=”http://www.somedomain.com/article1.html”

Source:-http://searchengineland.com/google-creates-metatags-to-help-id-original-news-sources-56115

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What is standout,Sydication source and Canonical

Publisher metadata tags
Google News indexes tens of thousands of articles a day, but not all are created equal. Publishers can now use three tags to help us determine which URL we should consider the most important version of an article:

standout can be used to indicate which URL should be credited with the standout journalism behind a breaking news story.
 
syndication-source can be used when an article is a slight modification of another article, such as a wire story.
 
rel=canonical can be used when you have the exact same content in two places on your sites, and want to indicate which URL should be prefered in search results.
Please note that information conveyed by these publisher tags are requests, and are used in conjunction with other signals.

Technical implementation

The preferred method is to use linktags in the <head> element of the relevant article. For example:

<link rel="standout" href="http://www.example.com/scoop_article_100.html"/>
<link rel="syndication-source" href="http://www.example.com/wire_article_100.html"/>
<link rel="canonical" href="http://www.example.com/canonical_article_100.html"/>

When the href URL points to itself, we will interpret the linktag as a self-citation. When the href URL points to another article page, we will interpret the linktag as pointing to an external source -- in other words, as an out-citation.

Standout and syndication-source tags are also available as standard HTML metatags, which belong in the <head> element of the article page:

<meta name="syndication-source" content="http://www.example.com/wire_story_100.html" />
<meta name="standout" content="http://www.example.com/scoop_article_100.html"/>

When to use each metadata tag

Any particular article will typically have, at most, one type of these metadata tags.

standout

If your news organization breaks a big story, or publishes an extraordinary work of journalism, you can indicate this by using the standout tag. When determining whether to use this tag for your own article, consider whether that article meets the following criteria:

Your article is an original source for the story.
Your organization invested significant resources in reporting or producing the article.
The article deserves special recognition.
You haven't used standout on your own articles more than seven times in the past week.
In addition, we strongly recommend citing standout articles from other publishers when your own article draws from that standout piece of journalism. When determining whether to use this tag to cite the work of others, consider the following criteria:

The publisher's article was the original source for the story you are now reporting.
The original source invested significant resources in reporting or producing the article.
You know that the original article deserves special recognition.
If a piece draws on multiple pieces of standout work, you can use the standout tag multiple times in the header of the article. Also, citing standout articles from other publishers does not count against the limit of seven self-citations per week.

If we find sites abusing the standout tag, we may, at our discretion, either ignore that site's tags or remove the site from Google News.

syndication-source

If you are a publisher who syndicates content, such as a wire service, or you are a republisher of syndicated content, then you can use the syndication-source tag.

Scenarios:

If you publish an article and syndicate it to other sites: Use syndication-source in the <head> of your article and make the href point to the original article's URL. You can also instruct sites that republish your syndicated content to use syndication-source in the <head> of their articles, and make their href point to your original article.
If you re-publish a syndicated article: Use syndication-source in the <head> of your articles, and make your href point to the original version of the article.
If you re-publish a syndicated article, but you don't know the specific URL for the original article: Use syndication-source in the <head> of your article, and make your href point to the domain of the original publisher.
 
rel=canonical

If you are a publisher who often mirrors content across your collection of sites, perhaps using different formats such as PDF and HTML for the same content, then you can use the rel=canonical tag.

Source:-http://support.google.com/news/publisher/bin/answer.py?hl=en&answer=191283

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