Schema.org

Schema.org is a reference website that publishes documentation and guidelines for using structured data mark-up on web-pages (called microdata). Its main objective is to standardize HTML tags to be used by webmasters for creating rich results (displayed as visual data or infographic tables on search engine results) about a certain topic of interest. It is a part of the semantic web project, which aims to make document mark-up codes more readable and meaningful to both humans and machines. Schema.org is an initiative launched on June 2, 2011, by Bing, Google and Yahoo! (operators of the world's largest search engines at that time) to create and support a common set of schemas for structured data markup on web pages. In November 2011, Yandex (whose search engine is the largest in Russia) joined the initiative. They propose using the schema.org vocabulary along with the Microdata, RDFa, or JSON-LD formats to mark up website content with metadata about itself. Such markup can be recognized by search engine spiders and other parsers, thus granting access to the meaning of the sites (see Semantic Web). The initiative also describes an extension mechanism for adding additional properties. In 2012, the GoodRelations ontology was integrated into Schema.org. Public discussion of the initiative largely takes place on the W3C public vocabularies mailing list. Much of the vocabulary on Schema.org was inspired by earlier formats, such as microformats, FOAF, and OpenCyc. Microformats, with its most dominant representative hCard, continue (as of 2015) to be published widely on the web, where the deployment of Schema.org has strongly increased between 2012 and 2014. In 2015, Google began supporting the JSON-LD format, and as of September, 2017 recommended using JSON-LD for structured data whenever possible. Despite the advantages of using Schema.org, adoption remained limited as of 2016. A survey in 2016 of 300 US-based marketing agencies and B2C advertisers across industries showing only 17% uptake.