Request for Comments (RFC) form the documentation of the Internet. There are currently 5298 RFCs however many of these are actually updates to earlier RFCs. Once an RFC has been written and published it will remain unchanged. If there needs to be updates or additions to the topic that the RFC addresses then a new RFC is issued which obsoletes the previous one. RFCs first start out as Internet Drafts (ID) which are documents that only exist for a few months before they either need to be updated or become approved for RFC status. RFC activity falls under the umbrella of the Internet Engineering Task Force (IETF). Statistics on RFCs can be obtained from IETF document statistics . An excellent site to search for RFCs or IDs is the RFC Editor site
On the 7th of April 2009 the RFC turned 40. To mark this anniversary RFC 5540 was created which describes some of the changes that have occurred recently. On the 30th anniversary RFC 2555 was released which provides reflections from some icons in the Industry.