There's no doubt that the traditional material has a massive influence on contemporary singer/songwriters in the folk genre. I wonder, however, how often it works the other way and how many people go back and rediscover the traditional material from hearing modern interpretations - and even, from there, go on to dig into the social and political history behind the songs. Its certainly works both ways for me. It's that two-way interaction between the past and the present that makes folk music such a joy and, of course, what keeps it alive and relevant.