Wandex
Wandex was the first ever search engine that was usable for the World Wide Web (prior to the creation of the World Wide Web, other search engines existed that searched through files themselves). Wandex was created in 1993 [1] by Matthew Gray using a Perl script. Wandex itself was based on the World Wide Web Wanderer, which merely listed web sites (something which was done by other scripts prior to the World Wide Web Wanderer).
Ordinary people would think that the trivia of what is the world's first search engine (Wandex) would be important. It was mentioned in a blog trivia post [2] and in joke site Dribbleglass's useless facts page [3].
In spite of this, the wise people at Wikipedia decided that Wandex was not notable enough for its own article [4], instead lumping it in with their article on the World Wide Web Wanderer [5], so that this trivia fact is forever obscured from the annals of time.
Perhaps because Google replaced Wandex (with a good many search engines in between), Google today makes almost no mention of Wandex in a search on the topic [6], and it seems that Wikipedia has supported this by trying to obscure its existence in the same way.