It's extremely common for RFCs to be cited in support of opinions (including Serverfault Q&A's), but the average IT employee has a very poor understanding in regards to which RFCs define standards and which ones are purely informative. This should be no surprise: system administrators of all experience levels typically avoid glazing their eyes at RFCs unless they have no choice but to.
On a site like ours, it is extremely important that we don't perpetuate common misunderstandings in our upvoted answers. Random users cruising in from search engines are going to assume that upvotes with no disputing comments are sufficient indicators of vetting. Recently I stumbled across an answer from 2011 making it apparent that this is definitely not getting caught in some cases as we upvote and probably warrants some efforts to inform our community and the internet at large.
So without further ado, how does one differentiate between a RFC that is quotable as an internet standard and one that is purely informative?