This time I will bite... Guest said "I did a Google search yesterday using the keywords "American folk music" and Mudcat never even turned up." and was challenged.
Assuming Guest just worked through all the pages that Google yeilded; looking for a direct link to Mudcat (and ignoring the "similar results excluded bit Google gives), the fact of the matter is that Guest spoke the truth - or at least I tried the same search with the same results as Guest.
There are of course other issues here, probably best highlighted by Amos...
...but, the question in my mind is why do so many people need to leap in and make a row and "justify" Mudcat?...
Jon