The discussion has brought many interesting thoughts and posts about how folk songs develop, what should be in and what should not and though it has not been free from rancour and point-scoring, it has never descended to the level where I felt that the mods were about to step in and close the thread. When he frees himself from his profound disputatious tendencies, (not that often, I'll agree), I find much to sympathise and agree with in what Jim Carroll writes. His views are clear and unchanging and in many ways that is admirable.
If we are to take a wider view and step out of the small broom cupboard of Mudcat for a while, we find quickly that we are in a different world. Here is an example of what I mean. The influential, very widely used American website and some time magazine, Folk Alley is a place that I visit from time to time. It avoids analysis, takes an uncritical, inclusive approach and avoids the sort of internecine rows that Mudcat revels in. Generally, it does not cater for my fairly purist views, but every time I go there I find something of interest. I had remembered that they had held a poll to establish The 100 Essential Folk Songs and by that they meant recorded performances - no attempt was made to define what was allowed. Here are the results 1-100 in terms of votes:-

   This Land is Your Land - Woody Guthrie
    Blowin' in the Wind - Bob Dylan
    City of New Orleans - Steve Goodman
    If I Had a Hammer - Pete Seeger
    Where Have All The Flowers Gone - The Kingston Trio
    Early Morning Rain - Gordon Lightfoot
    Suzanne - Leonard Cohen
    We Shall Overcome - Pete Seeger
    Four Strong Winds - Ian and Sylvia
    Last Thing On My Mind - Tom Paxton

    The Circle Game - Joni Mitchell
    Tom Dooley - The Kingston Trio (Trad)
    Both Sides Now - Joni Mitchell
    Who Knows Where The Time Goes - Sandy Denny
    Goodnight Irene - The Weavers (Trad)
    Universal Soldier - Buffy St Marie
    Don't Think Twice - Bob Dylan
    Diamonds and Rust - Joan Baez
    Sounds of Silence - Simon & Garfunkel
    The Wreck of the Edmund Fitzgerald - Gordon Lightfoot

    Alice's Restaurant - Arlo Guthrie
    Turn, Turn, Turn - The Byrds (Pete Seeger)
    Puff The Magic Dragon - Peter, Paul and Mary
    Thirsty Boots - Eric Andersen
    There But For Fortune - Phil Ochs
    Across The Great Divide - Kate Wolf
    The Night They Drove Old Dixie Down - The Band (Robbie Robertson)
    The Dutchman - Steve Goodman
    Matty Groves - Fairport Convention (Trad)

    Pastures of Plenty - Woody Guthrie
    Canadian Railroad Trilogy - Gordon Lightfoot
    Ramblin' Boy - Tom Paxton
    Hello In There - John Prine
    The Mary Ellen Carter - Stan Rogers
    Scarborough Fair - Martin Carthy (Trad)
    Freight Train - Elizabeth Cotton
    Like a Rolling Stone - Bob Dylan
    Paradise - John Prine
    Northwest Passage - Stan Rogers

    And The Band Played Waltzing Matilda - Eric Bogle
    Changes - Phil Ochs
    Streets of London - Ralph McTell
    Gentle On My Mind - John Hartford
    Barbara Allen - Shirley Collins (Trad)
    Little Boxes - Malvina Reynolds
    The Water is Wide - Traditional
    Blue Moon of Kentucky - Bill Monroe
    No Regrets - Tom Rush
    Amazing Grace - Odetta (Trad)

    Catch The Wind - Donovan
    If I Were a Carpenter - Tim Hardin
    Big Yellow Taxi - Joni Mitchell
    House of the Rising Sun - Doc & Richard Watson (Trad)
    Kisses Sweeter Than Wine - The Weavers
    Tangled Up In Blue - Bob Dylan
    The Boxer - Simon and Garfunkel
    Someday Soon - Ian and Sylvia
    500 Miles - Peter, Paul and Mary
    Masters of War - Bob Dylan

    Wildwood Flower - Carter Family
    Can The Circle Be Unbroken - Carter Family
    Can't Help But Wonder Where I'm Bound - Tom Paxton
    Teach Your Children - Crosby, Stills Nash & Young
    Deportee - Woody Guthrie
    Tecumseh Valley - Towns Van Zandt
    Mr. Bojangles - Jerry Jeff Walker
    Cold Missouri Waters - James Keeleghan
    The Crucifixion - Phil Ochs
    Angel from Montgomery - John Prine

    Christmas in the Trenches - John McCutcheon
    John Henry - Traditional
    Pack Up Your Sorrows - Richard and Mimi Farina
    Dirty Old Town - Ewan MacColl
    Caledonia - Dougie MacLean
    Gentle Arms of Eden - Dave Carter
    My Back Pages - Bob Dylan
    Arrow - Cheryl Wheeler
    Hallelujah - Leonard Cohen
    Eve of Destruction - Barry McGuire

    Man of Constant Sorrow - Ralph Stanley (Trad)
    Shady Grove - Traditional
    Pancho and Lefty - Townes Van Zandt
    Old Man - Neil Young
    Mr. Tambourine Man - Bob Dylan
    American Tune - Paul Simon
    At Seventeen - Janis Ian
    Bridge Over Troubled Water - Simon & Garfunkel
    Road - Nick Drake
    Tam Lin - Fairport Convention (Trad)

    Ashokan Farewell - Jay Ungar and Molly Mason
    Desolation Row - Bob Dylan
    Love Is Our Cross To Bear - John Gorka
    Hobo's Lullaby - Woody Guthrie
    Urge For Going - Tom Rush
    Return of the Grievous Angel - Gram Parsons
    Chilly Winds - The Kingston Trio
    Fountain of Sorrow - Jackson Browne
    The Times They Are A Changing - Bob Dylan
    Our Town - Iris Dement
    Leaving on a Jet Plane - John Denver

Now, to my way of thinking less than 10% of that list are folk songs and an even smaller percentage are of performances of folk songs that I would enjoy - Anne Neilson comes closest to my idea of what it's all about when she writes:-
So, my bottom line is that a traditional song (handed down orally etc.) is a special thing, particularly when it has come from performers of the calibre of Jeannie Robertson etc. -- but there is no bar to another song becoming equally significant….
We have to accept that the list is indicative of American opinion even though there are more songs that are out and out pop songs than out and out folk songs. If we want to inculcate people towards our own approach and views, we have to proceed in a way that demonstrates why we love what we call 'authentic' without being didactic or precious in our methods.