A distributed document retrieval system which started as a campus wide information system at the university of minnesota, and which was popular in the early 1990s.
Gopher is defined in rfc 1436. The protocol is like a primitive form of http (which came later). Gopher lacks the mime features of HTTP, but expressed the equivalent of a document's mime type with a one-character code for the "gopher object type". At time of writing (2001), all Web browers should be able to access gopher servers, although few gopher servers exist anymore.
tim berners-lee, in his book "Weaving The Web" (pp.72-73), related his opinion that it was not so much the protocol limitations of gopher that made people abandon it in favor of HTTP/html, but instead the legal missteps on the part of the university where it was developed:
"It was just about this time, spring 1993, that the University of Minnesota decided that it would ask for a license fee from certain classes of users who wanted to use gopher. Since the gopher software being picked up so widely, the university was going to charge an annual fee. The browser, and the act of browsing, would be free, and the server software would remain free to nonprofit and educational institutions. But any other users, notably companies, would have to pay to use gopher server software.
"This was an act of treason in the academic community and the Internet community. Even if the university never charged anyone a dime, the fact that the school had announced it was reserving the right to charge people for the use of the gopher protocols meant it had crossed the line. To use the technology was too risky. Industry dropped gopher like a hot potato."