Rich Snippets - Webmaster Google- Types of Rich Snippets

You can mark up your structured HTML content any of three formats: microdata,microformats, or RDFa. You can use whichever standard you prefer. You don't need any prior knowledge of these formats, just a basic knowledge of HTML.

(Note: Marking up your data for rich snippets won't affect your page's ranking in search results, and Google does not guarantee that markup on any given page or site will be used in search results.)

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. To see an example of a short HTML block showing basic contact information for Bob Smith

Marking up data using microformats

Microformats are simple conventions (known as entities) used on web pages to describe a specific type of information —for example, a review, an event, a product, a business, or a person. Each entity has its own properties. For example, a Person has the properties name, address, job title, company, and email address.

In general, microformats use the class attribute in HTML tags (often <span> or <div>) to assign brief and descriptive names to entities and their properties. To see an example of a short HTML block showing basic contact information for Bob Smith.

Marking up content using RDFa

RDFa is a way to label content to describe a specific type of information, such as a restaurant review, an event, a person, or a product listing. These information types are calledentities or items. Each entity has a number of properties. For example, a Person has the properties name, address, job title, company, and email address.

In general, RDFa uses simple attributes in XHTML tags (often <span> or <div>) to assign brief and descriptive names to entities and properties. To see an example of a short HTML block showing basic contact information for Bob Smith.