CrossRef works behind the scenes with Google to facilitate the crawling of content on publishers' sites and sets the policies and guidelines governing publisher participation in the initiative. As well as enabling CrossRef Search, the partnership with Google also means that full-text content from the publishers is also referenced by the main Google.com index in its more general searches. Participating publishers are: American Physical Society; Annual Reviews; Association for Computing Machinery; Blackwell Publishing; Institute of Physics Publishing; International Union of Crystallography; Nature Publishing Group; Oxford University Press; and John Wiley & Sons, Inc.
The CrossRef Search pilot will run through 2004 to evaluate functionality and to gather feedback from scientists, scholars, and librarians for the purpose of fine-tuning the program. Participating publishers are also investigating how DOIs can be used to improve indexing of content and enable persistent links from search results to the full text of content at publishers' sites. CrossRef is also in discussion with other search engines.