True but I think people often assume, mistakenly, that SO will have a lower cost than RTFM. A great example is Postgres authentication, there are hundreds if not thousands of questions on this topic on SO, almost all of which would be answered by reading the very concise, very accessible section of the Postgres manual.

Not suggesting there's anything wrong with using SO for this but that the cost of reading the manual for these purposes would actually be far lower.