Song for Ireland, The Holy ground, Witch of the Westmerlands... Dylan, Ochs, McCutcheon, Lightfoot, Christy Moore, Dougie MacLean's great songs, Silly Wizards....etc.
It is my belief that 'folk' is an artifical tag.
Traditional is also a bit loose, because it ends up being a term annalogous to HALL OF FAME...
I think we have a great deal to say about what music is considered trad, by playing what you enjoy. Let the test of time be the Judge, not the opinionated bastard sitting next to ya...
Also, we tend to think of folk music as acoustic, words oriented and/or dance, by dead people, and of a specific form that we can judge, critique, and cubbyhole.
The living part of folk is often forgotten,... that songs are being written right now that will be considered Folk in years to come... And these songs will inevitably be accompanied by Two or Three thousand that will be forgotten... How can we possibly know? Look for what will be interesting in 50 or 100 years... As for now, music written in the folk idiom will do,... but quality and timelessness are intangible to us...
Perhaps those who study trad songs will find the key,...But it is definately true that those who only listen to the trends and the sexys, or the SS who speaks for a particular gender, relationship, generation, period of time, etc.... will tend to produce for the time being, or for money, fame, and hormones...