The Internet Engineering Steering Group (IESG) operates in the same manner as other steering committees: "it decides on the priorities, topics under investigation, and order of business of an organisation and oversees the general course of its activities." The Internet Engineering Steering Group (IESG) manages/oversees the operations of the Internet Engineering Task Force (IETF); which is an organisation, comprised of working group volunteers, who engineer short-medium term projects related to Internet Standards (protocols etc). The Internet Engineering Steering Group (IESG) adheres to procedures, rules and conduct that are provided by the Internet Society (ISOC) Trustees.
The Internet Engineering Steering Group (IESG) is presided over by a 'Chair' and is comprised of Area Directors (ADs); the IESG Chair and Area Directors (ADs) are assigned by the Internet Architecture Board (IAB). Therefore, the IAB, who are in-turn an advisory body of the Internet Society (ISOC), influences the activities of IESG by picking the people who are employed by the IESG. The IESG Area Directors (ADs) oversee the work of the IETF working groups, and it is they who decide whether working group drafts are published as a RFC document; and therefore can become an Internet Standard ('STD' subseries documents). It should be clear that IESG members yield authority in the Internet Standards process.
How the Internet Standards process is conducted is outlined in RFC 2026 (S. Bradner, 1996): it describes a process where IETF working groups drafts are submitted with a Experimental or Informational status and the RFC Editor and IESG Area Directors (ADs) review these submissions and decide the next action to be taken. RFC 2026 was the third revision of the Internet Standards Process - which outlines the role of the IESG - the previous revisions were published in RFC 1310 (Lyman Chapin, 1992) and RFC 1602 (1994). Therefore, while the IESG's role has largely remained the same since it's creation in the late 1980's (when the IEFT was created by the IAB), how it manages the Internet Standards process has been altered to improve it's performance.
The members of the IESG serve as individuals, and do not represent a government, organisation or company. The leadership of the IESG is provided by a 'chair'. Previous chairs of the IESG have been: