As millions of people came online iduring the late 1990s, they needed help figuring out what each web page was about, and how to find what they were looking for. Web indexes and search engines sprang up. When Google was founded in September 1998, it had to compete with the information retrieval algorithms and techniques—nicknamed “secret sauce”—used by Lycos, Yahoo, and other companies.

Technically speaking, Google added two innovations: highly efficient processes for crawling web pages to index their text, and a new way of ranking a page’s relevance based on the number and quality of pages that linked to it. In addition, its interface was refreshingly clean: In an internet then pervaded by pages with lists of lists, Google offered a spare alternative, with just a box to type search terms and a search button.

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