The Sitemaps protocol allows a webmaster to inform search engines about URLs on a website that are available for crawling. More at Wikipedia
Site map - A site map is a list of pages of a web site accessible to crawlers or users.
Biositemap - A Biositemap is a way for a biomedical research institution of organisation to show how biological information is distributed throughout their Information Technology systems and networks.
Metadata - Metadata is loosely defined as data about data.
Resources of a Resource - Resources of a Resource is an XML format for describing the content of an internet resource or website in a generic fashion so this content can be better understood by search engines, spiders, w...
Yahoo! Site Explorer - Yahoo! Site Explorer is a Yahoo! service which allows viewing of information on websites in Yahoo!'s search index.
Google Webmaster Tools - Google Webmaster Tools is a no-charge web service by Google for webmasters.