BACK in the early days of the World Wide Web, users could consult a directory of servers personally compiled by its creator, Tim Berners-Lee, to help them find their way around. A snapshot of this directory from 1992, provided by CERN, shows people used it to link to everything from physics journal abstracts to science fiction reviews and song lyrics.
As the web exploded in popularity, personal recommendations could not keep up with the growth in new sites. To help people navigate this expanding resource, commercial search engines like AltaVista, Yahoo and ultimately Google sprang up. These used software such…
