"On the Internet@ it is common practice to permit anonymous access to various services. Traditionally@ this has been done with a plain-text password mechanism using ""anonymous"" as the user name and using optional trace information@ such as an email address@ as the password. As plain-text login commands are not permitted in new IETF protocols@ a new way to provide anonymous login is needed within the context of the Simple Authentication and Security Layer (SASL) framework."
RFC 4505-2006 history
2006RFC 4505-2006 Anonymous Simple Authentication and Security Layer (SASL) Mechanism