Vendor lineage
Ranked pages by who linked to them rather than how often they said the word - and was nearly sold to AltaVista for a million dollars.
Larry Page and Sergey Brin met at Stanford in 1995 and began a research project in January 1996 called BackRub, which analysed which pages linked to which. The insight was that a link is a vote, and that votes from well-linked pages should count for more. They called the resulting algorithm PageRank.
Search engines at the time largely ranked results by how often a search term appeared on a page, which is trivially easy to game and was being gamed heavily. PageRank measured something a page's own author does not control: who else thought it was worth linking to.
In 1998 Page and Brin tried to sell PageRank to AltaVista for $1M, intending to go back to their studies. AltaVista did not buy it. They registered google.com on 15 September 1997 - the name a misspelling of googol, the digit one followed by a hundred zeros - and incorporated Google Inc. on 4 September 1998 in a friend's garage in Menlo Park.
The first cheque came from Andy Bechtolsheim, a co-founder of Sun Microsystems, followed by $25M from Kleiner Perkins and Sequoia in 1999. The IPO in 2004 raised $1.67B.
The homepage was deliberately bare while every competitor was becoming a portal. That was partly conviction and partly circumstance - neither founder was much of an HTML author - but it landed at exactly the moment AltaVista and its peers were adding shopping, email and news to the front page of a search engine.
A footnote worth keeping: RankDex, built by Robin Li in 1996, was exploring link-based ranking on a similar timeline. Li patented that work and later founded Baidu. PageRank was not the only idea of its kind; it was the one that got built into a company that wanted to be a search engine.