All major search engines claim that they strive to present search results to users with the highest quality. But the
business of search engine is business. What they won't tell us is that there're many business reasons for every major search engine updates.
Search engine traffic is hot commodity - it's free and has higher conversion rate since the searchers are very close to make their buying
decisions. The downside of the search traffic for webmasters is that they don't have control at all. Your sites may be ranked #1 today, but
nowhere next day.