Uncommon hypertext network protocols

Specification for the Gemini protocol, a hypertext-centric protocol that operates over TCP/IP as an alternative to HTTP and HTML. It is described as a heavier alternative to Gopher instead of a lighter alternative to HTTP.

Wikipedia entry regarding the Gopher protocol. Gopher is a protocol that predates HTTP. It defines its own hypertext format.

Specification for the very minimal experimental protocol, called spartan, inspired by Gemini and Gopher.