The mystery around google search:
1)500 improvements are made to search algorithm every year to get the best results.
2) SandBox--Conduct live experiments on real users; a very small fraction of the actual google traffic is sent through a sandbox to calculate the metrics.
3) Spelling suggestions(Full Page Replacement)--The user can use the escape hatch when the search suggestions went wrong; Escape hatch would pass the test only if the user clicked it 1 in every 50 times.
Every commentator in the video(refer to the link below) at the end emphasizes that they do these changes keeping in mind the user(makes me wonder is this the reason why our searches are not private anymore and so called personalized searches)
Hope you all find this interesting, link to the above pointshttp://techcrunch.com/2011/08/25/tweaking-the-algorithm-google-gives-a-small-peek-behind-the-curtains/