schema.org
Google, Bing and Yahoo have come up with a new initiative in order to assist with a common set of schemas for structured data markup. This resource is designed for webmasters to enable them to easier present their information to search engines.
Google already supports structured markup and examples can be seen in via rich snippets which pop up in reviews of products, events, recipes, movies…etc.
Supported markup types include:
- Creative works: CreativeWork, Book, Movie, MusicRecording, Recipe, TVSeries
- Embedded non-text objects: AudioObject, ImageObject, VideoObject
- Event
- Organization
- Person
- Place, LocalBusiness, Restaurant
- Product, Offer, AggregateOffer
- Review, AggregateRating
Full list is available here: http://schema.org/docs/full.html
Usual treatment of microdata, microformats and RDFa has changed and with schema.org it has been decided in favour of only microdata as main standard. This should not cause concern with those who already have other standards implemented as Google promises support for those as well. Do not mix different standards on the same page though.
To test out your rich snippets use this tool:

Link to this page

