How do website pages get indexed by the search engines?

@dustin.green 

Website pages get indexed by search engines through a process called "crawling." Search engines use automated programs called "bots" or "spiders" to follow links from one page to another, discover new pages, and index their content. The frequency of crawling and the amount of content indexed depends on factors such as the relevance and quality of the content, the structure of the website, and the preferences set by the website owner in the search engine's Webmaster Tools. Submitting a sitemap and using relevant keywords, meta descriptions, and alt tags can also help improve the chances of a website's pages getting indexed by search engines.