The Internet Architecture Board (IAB) must approve all RFCs before they are placed in the public domain. Typically, the information in RFCs is designed for developers and other highly technical readers.
Generally, for your information (FYI) documents appear as a subset of the RFCs. FYIs contain information that does not deal with Internet standards. FYIs contain Internet information of a more general nature. For example, FYI documents include a bibliography that list introductory TCP/IP books and papers. FYI documents provide an exhaustive compendium of Internet-related software tools. Finally, FYI documents include a glossary of Internet and general networking terms.