Bing, Google and Yahoo have launched an search engine marketing initiative together regarding indexing content or better to provide a set of additional meta data to index special parts of content. Following the cooperation to standardize sitemaps now schema.org is dedicated to standardize indexing of additional aka supplemental data.
Schema.org concerns the indexing of semantic data, which up to now is primarily used for specific content and already known by the Rich Snippets format of Google. This kind of indexing uses particular meta data to provide special information and to enhance search results with e.g. up to date event data, reviews or special topical specifications. The aim of the initiative is to standardize the meta data to enable webmasters to provide a set of meta data readable to all search engines and other relevant services.
The initiative schema.org has been announced within all official blogs of the participants. The website schema.org serves to provide the specifications and to collaborate with developers on standardization and to create new formats. For more visit the schema.org homepage.