A site map (or sitemap) is a list of pages of a web site accessible to crawlers or users. It can be either a document in any form used as a planning tool for Web design, or a Web page that lists the pages on a Web site, typically organized in hierarchical fashion.
* Learn about sitemaps 
* Build and submit a sitemap
* Manage sitemaps with the Sitemaps report
* Simplify multiple sitemap management
* Use a sitemap to indicate alternate language pages
* Creating a Google News Sitemap
* Video sitemaps
* Image sitemaps
* Feature phone sitemaps
Sitemaps make relationships between pages and other content components. It shows shape of information space in overview. Sitemaps can demonstrates organization, navigation, and laneling system.
Sitemaps are an easy way for webmasters to inform search engines about pages on their sites that are available for crawling - sitemaps.org
This document describes the XML schema for the Sitemap protocol - sitemaps.org/
PageMaps is a structured data format that Google created to enable website creators to embed data and notes in their webpages - support.google.com
You should test your sitemap syntax before you submit it. To test an unsubmitted sitemap:
In a Linked CSE the specification of the search engine is hosted on your website. In a Google Stored CSE the specification is stored at Google.
The robots exclusion standard, also known as the robots exclusion protocol or simply robots.txt, is a standard used by websites to communicate with Web Crawlers and other web robots - wikipedia
Schema.org is an initiative launched on 2 June 2011 by Bing, Google, Yandex (whose search engine is the largest one in Russia) and Yahoo to “create and support a common set of schemas for structured data markup on web pages.”