Hippias searches a small set of Associate Sites and all the pages they link to, with the exception of a few pages that Hippias is told to avoid, such as personal homepages and the major search engines discussed above. This procedure, in turn, passes Hippias' editorial control over to the experts that manage the associate sites. By simply linking their index to a page, these editors are also instructing Hippias to include it in the search window. This site contains many resources in the philosophy of mind and links to online philosophy papers. Suber's Guide is a comprehensive collection of philosophy resources on the internet, continually updated.
Noesis is an index and search engine of philosophical content written by professional philosophers.
It indexes essays, lectures and other course materials, images, graphs, charts, book and article reviews, primary texts, bibliographies, chronologies, and glossaries. Philosophy in Cyberspace is an extensive, annotated index of philosophy resources organized into over 50 topical categories and updated regularly. It uses the same system of peer-review that Hippias uses to limit the range of responses to ancient and medieval resources. The Perseus Project includes several of its own search engines that provide access to information not covered by Hippias, including standard Greek editions of works by Plato and Aristotle. The overall quality of Hippias is determined by a system of peer-review.