In a 2003 interview, Sergey Brin said the following:

Some say Google is God. Others say Google is Satan. But if they think Google is too powerful, remember that with search engines unlike other companies, all it takes is a single click to go to another search engine.

Search engines and Web sites are not like other high tech products. It takes money to swap out a phone or a computer. It takes time — not to mention fear and risk — to change operating systems. But we can go to any search engine almost immediately, for free. There are thousands of them. Each country has its own leading search engine. Yet, 66 percent of all Internet searches are done on Google.

Why?

• First, Google earned our trust by being excellent: it performs fast, accurate searches.
• Second, it became habit to use Google.
• Third, Google innovates aggressively. This company is never satisfied. It never sits back to enjoy its perch at the top of the Internet world. In addition to constantly perfecting search, Google is now into mapping, phones, operating systems, productivity, applications, etc. When you stop innovating, you backslide. Always.

Trust. Consumer habit. Innovation. All three keep Google on top.

Like its search engine, Google’s lessons are free to use and apply.