In early 1996, two PhD students at Stanford University began collaborating on a search engine they called
BackRub. The difference between their project and other search engines of the day was that BackRub used
a unique technique: analyzing the backlinks pointing to a website to determine its relevance for a particular
Citation notation—common in academia—was the underlying concept behind BackRub’s ranking engine.
If one source is cited frequently by other documents, it usually means that it’s more important and relevant.
On the Internet, a backlink is, in effect, a citation.
During 1998, these two enterprising engineering students launched Google. This new search engine was built around a technology they dubbed PageRank, which was based on BackRub’s ranking engine. By the year 2000, Google was powering the searches for AOL, Yahoo, and various other major online providers.
The company had raised over $25 million in funding, and had come to essentially dominate the
search engine landscape.
Source: The SEO Business Guide