Google's Secret Weapon

Compared with companies such as eBay (EBAY Quote) and Amazon (AMZN Quote), "Google is much more vulnerable to competitive entry, because the technology is well-known, server farms are becoming less and less expensive, and users don't become more likely to use Google based on what other users do," John Hussman, president of the Hussman Investment Trust, wrote in a note to clients in October to explain why he doesn't own Google shares.

"Little prevents competitors from gradually sniping market share except the slight neuromotor conditioning created by repeatedly typing the company name."

In fact, far from seeing market share sniped away, Google has only gotten more popular. According to researcher HitWise, it commanded about 65% of the search market in October, up from about 62% a year ago.

Yahoo!, Microsoft, and IAC/InterActive's(IACI Quote) Ask.com, with a 21%, 7%, and 5% share respectively, all saw their market share slip over the same period.

When it comes to the quality of search results, the power of Google's -- or Microsoft and Yahoo!'s, for that matter -- algorithms is only part of the story. The amount of data the algorithms have to feed off of also plays a critical role in the relevance of search results. Algorithms are fundamentally rooted in statistics and probability, where data plays a crucial role in predicting the quality of future results.