I am looking for some documents on how Google crawl and index content. I read many “light” papers and articles on what you need to do to improve your ranking and make sure your content is properly indexed but I am looking for some more advanced technical documents on how Google crawl and index content.
The things I would like to know more about:
- What elements Google look for when it crawls: page content, URLs format, keywords, description etc…
- How the index is updated?
Basically, I am trying to understand why some pages are indexed but not others even if the formats are similar. Why only 10% of my site’s pages appear when I do a search on the entire domain even if I can see on my server logs that Google crawled every single link.
The answers to both things are closely-guarded trade secrets, ostensibly to prevent gaming the system.
Also keep in mind that Google makes over 400 algorithmic changes per year, making it close to impossible for an outsider to be accurate and up-to-date. Short of working for Google, you’re likely not going to find an in-depth and accurate answer.
However, Matt Cutts, head of the web spam team, frequently provides the most accurate insights in how Google handles content, both on his blog and on the GoogleWebmasterHelp YouTube channel. It’s worth going through his content to get a much better understanding of Google’s methodology.