Backrub was an early search engine from the 1990s which is now regarded as the predecessor of the Google search engine and was personally developed and operated by Google founder Larry Page.
Work on the Backrub search engine began in 1996. It was a research project Larry Page, who studied at Stanford University at the time and was part of the team that worked on the Stanford Digital Library Project (SDLP). This project had set itself the goal of developing technologies which could create a universal digital library. As part of his thesis, Larry Page took up the issue of linking. His reflections on understanding link structure as a huge graph, later led to the development of the still significant PageRank algorithm.
Page named his project Backrub. A little later Sergey Brin, who had also worked on a similar study and research area, joined Page and from then on supported him in the development of the search engine.
First, the search engine returned a list of backlinks, whose ranking was designed depending on their importance. The two developers quickly realized that a search engine that would be based on PageRank would yield better results than existing technologies. At that time, search engines were exclusively fixated on how frequently a searched for keyword appeared on a web page. Page and Brin wanted to build Backrub on the principle that websites would be most relevant which had the most links.
After Backrub began indexing websites in March 1996, the index grew furiously fast. By August 1996, some 75 million pages had been indexed which combined, occupied a memory of 207 GB. Around 30 million HTML pages were among them, but even more e-mail addresses. In the year Google was created, Backrub had already indexed 25 million pages. Google Inc., was finally established on September 4, 1998 and the renaming of the search engine from Backrub to Google was decided.
The Backrub search engine was based on Java and Python. Page ran it on several Sun Ultras and Intel Pentiums with a Linux operating system. The primary database was at that time on a Sun Ultra II with a hard disk space of 28 GB. Until 2007, Backrub ran on servers at Stanford University. After that, Page and Brin operated their servers for a few months in the garage of their friend, Susan Wojcicki. She is in a senior position at Google Inc., today. After these premises had become too small, the Backrub servers moved for the second time. Besides Larry Page and Sergey Brin, Scott Hassan and Alan Steremberg were also involved in the technical development of Backrub.
With the search engine Backrub, Page and Brin laid the foundation for search engine optimization as it is known today. For many years, the targeted building of links was an elementary building block of SEO to improve ranking. Backrub, or more specifically their founders, can be credited with the fact that the number of external, incoming links influences ranking.