WHAT Is SNIPPET?? Crawling And Indexing?

please tell me about What is Snippet, Crawling and indexing.. how it will help me in SEO for my blog n website.

 

Do a "what is" search in Google for each term.

 

i didn't get the full them of it..??? kindly explain about it.

 

snippet , Here it is description....................................crawling.............................noticed by search engines.......................indexing................searchable in search engines

 

Snippet means a portion of the text/content in the website as displayed in the search engine results. Crawling means indexing by the search engine spiders. indexing means adding the text content of the site into the search engines' corpus so it becomes searchable and displayable to the searchers using the engine.

 

ok thanks dear....index should be on every page of ur website?