How does Google decide which few documents I really want?
By asking questions; more than two hundred of them. Like:
- How many times does this page contain your key words?
- Do the words appear in the title? In the URL (web address)?
- Do the words appear directly adjacent?
- Does the page include synonyms for those words?
- Is this page from a quality website? Or is it low quality, even spammy? What is this page’s PageRank? That’s a formula invented by our founders, Larry Page and Sergey Brin, that rates a webpage’s importance by looking at how many outside links point to it, and how important those links are.
Finally, we combine all those factors together to produce each page’s overall score and send you back your search results, about half a second after you submit your search.
منبع:دوره آموزشی power searching with google