Yes, SNMP has been around long enough for a few grandfathers to have used it. In version 1 there was not really a lot you could do. You could find the value of a system OID and set an OID if you really knew what you were doing. Version 2 added the ability to perform get bulk requests, rather than the old way of issuing strings of get next requests. Using get bulk was like being able to look at a whole page of a book, where get next was like having to ask for each word one at a time.
Version 3 added a very strong and flexible security mechanism along with some other minor features. For a long time version 3 seemed to scare people off because of the many options of the security models it uses. If you have been interested in SNMP v3 and want to know how it is implemented, see this Technical Reference.
If you want to know more about SNMP and how it works, see this educational paper.