Starting 2009, Google started using a new indexing and ranking algorithm which is different from what used to be the case in the years before.
A quick search on some names and here are the findings for the new indexing algorithm by google.
Google is giving higher ranking to brands and big names to appear on top of the result page.
Google used to make sure the Keyword is found in Title , URL and Description of the webpage, Now it seems results come up first even if keyword is just in Title or URL or Description or any combination.
The result of a particular page are not fixed and can move a bit up or down, depending on the data center which is pulling the content from.
Local Google engines, such as Google.ca results are different from Google.com (in .ca canadian pages seems to be injected within the general results, for example if you are search for the word Music a Book about Music in Amazon.ca might appear first.
With such a move it is harder for casual pages to get a high ranking, and by the way the Google Ranking is no longer relevant when it comes to search results.