(Cross-posted on the Inside Search Blog)

Today we’re announcing schema.org, a new initiative from Google, Bing and Yahoo! to create and support a common vocabulary for structured data markup on web pages. With schema.org, site owners and developers can learn about structured data and improve how their sites appear in major search engines. The site aims to be a one stop resource for webmasters looking to add markup to their pages.

Search engines have been working independently to support structured markup for a few years now. We introduced rich snippets to Google search in 2009 to help people find better summaries of reviews and people, and since that time we’ve expanded to new kinds of rich snippets, including recipes and events. We’ve been thrilled to see content creators across the web—from stubhub.com to allrecipes.com—add markup to their pages, and today we’re able to show rich snippets in search results more than 10 times as often as when we started two years ago.

We want to continue making the open web richer and more useful. We know that it takes time and effort for webmasters to add this markup to their pages, and adding markup is much harder if every search engine asks for data in a different way. That’s why we’ve come together with other search engines to support a common set of schemas, just as we came together to support a common standard for sitemaps in 2006. With schema.org, site owners can improve how their sites appear in search results not only on Google, but on Bing, Yahoo! and potentially other search engines as well in the future.

In addition to consolidating the schemas for the categories we already support, schema.org also introduces schemas for more than a hundred new categories, including movies, music, organizations, TV shows, products, places and more. As webmasters add this markup to their sites, search engines can develop richer search experiences. With webmaster feedback, we’ll be able to regularly publish new schemas for sites to use and, in turn, expand the list of queries with rich results. For webmasters who have already added microformats or RDFa currently supported by rich snippets, their sites will still appear with rich snippets on Google. You can learn more on our Webmaster Central Blog, Help Center and on schema.org.

Schema.org provides a wide variety of vocabularies webmasters can use to mark up their pages.

While this collaborative initiative is new, we draw heavily from the decades of work in the database and knowledge representation communities, from projects such as Jim Gray’s SDSS Skyserver, Cyc and from ongoing efforts such as dbpedia.org and linked data. We feel privileged to build upon this great work.

We look forward to seeing structured markup continue to grow on the web, powering richer search results and new kinds of applications.