Google has software that ranks Web sites based on their importance. Page rank and other factors determine where a site shows up in a Google search. The higher your site is in the results, the more visitors you'll get, which — if you're an e-commerce site — translates into more sales. If you use display advertising, it means more hits and therefore more ad revenue.It is amazing how Google has bluffed everyone into believing that its search responses are mathematical consequences of its patented Page Rank algorithm, with no human discretion. If fact, Google employs thousands of people to hand-tune those search results. If you got your web site by clicking the Feeling Lucky button, then your luck was probably that some Google employee hand coded it that way.
The algorithms that determine how a site is ranked are, of course, controlled by Google, and when Google tweaks those algorithms, there are winners and losers.
Google now has some monopoly power over who finds what on the web. The easiest way to avoid its influence is to use Yahoo search.
Update: Lifehacker writes:
If you spend as much time online as I do, you can pump a significant amount of personal information into the cloud every day. Think about what percentage of that cloud Google owns. For me, it's three years of work and personal email in Gmail, years of events in Google Calendar, phone calls and voicemail in Google Voice, documents and spreadsheets in Google Docs, web page viewing habits in Google Reader. To top it all off, Google also has a record of everything I search the web for every day in their logs. ...
If the thought makes you uncomfortable, it might be time for you to take a few personal information eggs out of Google's basket. Truth be told, since I moved to Yahoo Search, I've barely missed GOOG. At this point, the two leading search engines aren't that far apart when it comes to quality of results and features.