Syslog was developed in the 1980s by Eric Allman as part of the Sendmail project, and was initially used solely for Sendmail.
Others include the keyboard, mouse, RS232 and Centronics servers (built into the host I/O server), the null server (like Unix's /dev/null), and the logger server (like Unix's syslog).
A general standard outlining a logging system is the Syslog standard (described in RFC 5424), which allows the filtering and recording of log messages to be performed by a separate dedicated subsystem, rather than placing the onus on each application to provide its own ad hoc logging system.