BackRub

In 1996 two Stanford PhD students, Larry Page and Sergey Brin, built a search engine that ranked web pages by looking at the links pointing to them, which they called back links. So they called it BackRub.

It ran on Stanford’s own computers until it grew so busy that it used up too much of the university’s network capacity. By 1997 it needed its own home on the web, and a better name.

During a brainstorm, fellow student Sean Anderson suggested googolplex. Page preferred the shorter googol, the name for the number 1 followed by 100 zeros, a fitting word for an engine meant to organise a vast amount of information.

Anderson went to check whether the web address was free, but typed google.com instead of googol.com. Page liked the misspelling even better. He registered google.com on 15 September 1997.

The word googol has a story of its own. It was coined around 1920 by Milton Sirotta, the young nephew of the American mathematician Edward Kasner, who had asked the boy to invent a name for an enormous number.

Look closer: A child named the number; a typing slip named the company.