You can have a look at the GENDEX Database here.
Here’s a brief summary of just what it is (from Dick Eastman’s article):
GENDEX was a method of indexing genealogy information spread across many web sites. It was created by Gene Stark. His web site, www.gendex.com, was a genealogy search engine that indexed more than 22,000 online databases of genealogical information on 60 million people. That means you could search the data from many Web sites by visiting only one site. When you found something that looked worthwhile, you clicked on the name on www.gendex.com and then got transferred to the original source of information on another site.
The GENDEX site was shut down on April 22, 2004, apparently due to financial issues. I see that the domain name of gendex.com has now been re-issued to another company that is not involved with genealogy.
Now there is new hope for GENDEX; it has been “married” to The Next Generation. Multiple web sites running The Next Generation software are now supplying RSS feeds of their data, which is then merged together into one GENDEX site.
This is a very interesting development concerning GENDEX and genealogy information on the web in general.