1. "We chose our system name, Google, because it is a common spelling of googol."
[ Anatomy of a Search Engine, the paper that describes PageRank. ]
2. "Googol is the mathematical term for a 1 followed by 100 zeros. The term was coined by Milton Sirotta, nephew of American mathematician Edward Kasner, and was popularized in the book, "Mathematics and the Imagination" by Kasner and James Newman. Google's play on the term reflects the company's mission to organize the immense amount of information available on the web."
[ Google's Corporate site now ]
3. " 10^100 (a gigantic number) is a googol, but we liked the spelling "Google" better. We picked the name "Google" because our goal is to make huge quantities of information available to everyone. And it sounds cool and has only six letters. "
[ Google's Corporate page in 1999 ]
4. As Larry Page, the co-founder of Google.com narrates:
"Lucas Pereira: 'You idiots, you spelled [Googol] wrong!' But this was good, because google.com was available and googol.com was not. Now most people spell 'Googol' 'Google', so it worked out OK in the end."
[ Probably the correct version. ]
5. "The original founders were going for 'Googol', but ended up with 'Google' due to a spelling mistake on a check that investors wrote to the founders."
[ Wikipedia's opinion ]
{ Inspired by a discourteous commentary. }