It is amazing how Google supplies the most relevant information on any search term. I for one have sat down to think out how they do it because I know it will help our site rank better if we are able to think like them (Google).
One thing that comes to mind was Yellow Pages and how advert were tabulated and serialized alphabetically. Google could have used this same mechanism as stepping stone to build their algorithm (just my thought).
However, the history of search engine confirmed my thought in a way and How Stuff Works also broaden my knowledge about it.
Having insight on how Google crawl content with the intent of indexing the page can go a long way to help understand how to optimize our web pages for high rank on SERP.
One fact I know is that, search engine love blogs because they are updated on regular basis and arrangement of content is chronological, giving preference to new content. Sure, Google need enough sources of relevant information to present to her customers.
Beyond this, there are myriad factors that determine the rank of web page programmed within search engine algorithm- a mathematical instruction that tell computers how to complete assigned task. These instructions encapsulate ranking factors.
Yes, they have to employ this tactics in order to come up with the best and most appropriate content for a particular keyword in the midst of thousands of site optimizing and targeting the same term in the World Wide Web.
So, when a blog post or web page is published, search engine spiders are notified through services like ping. These spiders will come, crawl the links and content. They collect this information and store on a database where it would be processed, scaled on the available ranking factors to determine its position on the SERP before they are finally indexed and cached on the system for future use.
There are really more things that go behind the scene that can negatively impact on SEO effort especially when web pages are crawled and scaled for ranking. Simple internal issues like .htaccess. Robot.txt, could hinder search engine spider from crawling content if not well configured. Because they are among the simple files that guide search engine bots on how to crawl a site.
The infographic below from Quickspruot shows how Google crawl and index web pages and also highlighted major impediments that could hinder your website rank on SERP.