Deep Web Wiki

Search Beyond the Search Engine. Direct from the site: The Deep Web Wiki is a volunteer-led search organization that maintains a database containing detailed descriptions of so-called "Deep Web" sites that are either ignored or poorly indexed by the major search engines; it is estimated that ~95 to 99% of Web-accessible content cannot be reached using conventional web crawling methods. The Deep Web Wiki also contains other useful information sites that often are not popular enough to rank on the first few pages of search engine's results--despite their value.

The Deep Web Wiki depends on the efforts of Web users to build the wiki and improve the quality and accuracy of site descriptions. Contributions to the index can be made either anonymously or by signing up for a free membership that allows members to track their contributions and watch pages of interest. To further assist in this effort, we are recruiting topic Experts who can help point searchers to the most valuable resources in the surface and deep Webs.

It reminds me a little of Mahalo as it used to be, with the 'expert led' resources, and a bit like Knol. (Anyone remember that Google initiative? It's still out there, believe it or not.)

However, the emphasis is on finding useful resources, so it does take a different focus. It certainly found content and databases that I wasn't aware of, so if you're really stuck and/or want to explore the hidden/invisible/deep web. this is worth a try.