Unlike later search engines, like Aliweb, which attempt to index the web by crawling over the accessible content of web sites, W3 Catalog exploited the fact that many high-quality, manually maintained lists of web resources were already available. W3 Catalog simply mirrored these pages, reformatted the contents into individual entries, and provided a Perl-based front-end to enable dynamic querying.
W3 Catalog was retired on December 8, 1996.
- Oscar Nierstrasz (2 September 1993). "Searchable Catalog of WWW Resources (experimental)".
- "W3 Catalog History".
- Thomas R. Gruber, Sunil Vemuri and James Rice (December 1995). "Virtual documents that explain How Things Work: Dynamically generated question-answering documents". Knowledge Systems Laboratory, Stanford University.