Why use OpenSearch?
The web is a big place, and search engines that crawl the surface of the web are picking up only a small fraction of the great content that is out there. Moreover, some of the richest and most interesting content can not even be crawled and indexed by one search engine or navigated by one relevancy algorithm alone.
Different types of content require different types of search engines. The best search engine for a particular type of content is frequently the search engine written by the people that know the content the best.
OpenSearch helps search engines and search clients communicate by introducing a common set of formats to perform search requests and syndicate search results.
ref:http://www.opensearch.org/Documentation/Frequently_asked_questions
