Schema.org is a collection of microformats, introduced in Spring 2011 by Google, Yahoo and Microsoft.
The rationale for introducing this, is according to What is Schema.org? the following:
This site provides a collection of schemas, i.e., html tags, that webmasters can use to markup their pages in ways recognized by major search providers. Search engines including Bing, Google and Yahoo! rely on this markup to improve the display of search results, making it easier for people to find the right web pages.
Many sites are generated from structured data, which is often stored in databases. When this data is formatted into HTML, it becomes very difficult to recover the original structured data. Many applications, especially search engines, can benefit greatly from direct access to this structured data. On-page markup enables search engines to understand the information on web pages and provide richer search results in order to make it easier for users to find relevant information on the web. Markup can also enable new tools and applications that make use of the structure.A shared markup vocabulary makes easier for webmasters to decide on a markup schema and get the maximum benefit for their efforts. So, in the spirit of sitemaps.org, Bing, Google and Yahoo! have come together to provide a shared collection of schemas that webmasters can use.
Google understands business items, e.g. local business, events and products, structural information, and ratings and will then use these to display search data.
2 The Data Model and the Schemas
Schemas are a set of 'types', each associated with a set of properties. These types are arranged in a hierarchy.
2.1 Data Model
Read http://schema.org/docs/datamodel.html (quite vague) and better Getting Started
Browse the Full list of types, shown on one page at schema.org.
Schemas are organized in some ontological type hierarchy:
Example of a Schema: Thing > Organization > EducationalOrganization
This type inherits 4 properties from Thing and 14 properties from Organization. Values of these properties can either be simple types like text or numbers or complex types (i.e. other schemas).
<div itemscope itemtype="http://schema.org/EducationalOrganization"> <span itemprop="name">Palo Alto High School</span> <div itemprop="address" itemscope itemtype="schema.org/PostalAddress"> <span itemprop="streetAddress">50 Embarcadero Rd</span> <span itemprop="addressLocality">Palo Alto</span>, <span itemprop="addressRegion">CA</span> <span temprop="postalCode">94301</span> </div> List of Alumni <span itemprop="alumni" itemtype="http://schema.org/Person"> <span itemprop="name">John Doe</span> </span> <span itemprop="alumni" itemtype="http://schema.org/Person"> <span itemprop="name">Sarah Glames</span> </span> </div>
3 Political issues
According to a comment on Slashdot by Raenex, retrieved 17:21, 8 June 2011 (CEST), "crap" replaced by "technology" since we didn't make up our mind yet ....
The short summary: The "Sponsors" (read: cartel) may have patents on this [technology]. You can, for now, use the [technology] royalty free for markup only if you follow the standard. Non-cartel search engines are not granted such rights. In addition, future versions may not be royalty free. Your existing markup is safe, but any new versions or pages won't be.
The actual fine print:In addition, if the Sponsors have patent claims that are necessarily infringed by including markup of structured data in a webpage, where the markup is based on and strictly complies with the Schema, they grant an option to receive a license under reasonable and non-discriminatory terms without royalty, solely for the purpose of including markup of structured data in a webpage, where the markup is based on and strictly complies with the Schema. [..] Notwithstanding the foregoing, the Sponsors agree that no change that we make to these Terms of Service will terminate or modify the license granted under paragraph 1 above with respect to any use or implementation of the Schema occurring prior to the date that the change is published.
- Introducing schema.org: Search engines come together for a richer web, The Official Google Blog, June 2 2011.
- Does the Google/Bing/Yahoo Schema.org Markup Promote Invalid HTML?, by Jester, June 3 2011.