According to the marketing 'geniuses', in my local record shops, Folk is anything acoustic (apart from 'Folk Rock', of course)but excluding (acoustic) 'Country', 'Blues' and 'World', plus anything that doesn't fit into any other category, like Welsh Military bands.

I hope that's clear?

It isn't clear to me, but what do I know?

So ignore marketing people and any idiot who tries to tell you that there is "no accepted definition of Folk" (these are usually people who are desperate to play Rock Music in Folk Clubs) and read some of the zillions of threads on this Board, some of which give very clear definitions and explanations of what Folk Music is. And, no, most Rock/Pop Music probably won't be the "Folk Music of tomorrow".