I was wondering if they were successful worldwide, they seem to have mostly been in Europe (and their site has a German URL, haha), but they are American.
My Kelly Family memory is my earliest non-classical music memory, it was when I was 9 or so. I was on Usedom with my friend's family, and their concert was on TV, and my friend's older sister talked about how dirty they were 'n stuff.
The only other childhood memory I have that has anything to do with popular music was of the MTV show ten years after Kurt Cobain died.
But really, the Kelly Family was hugely successful when I was a child. Maybe that's why I'm such a pseudo gypsy nowadays.
So, relate your childhood music memories!
And tell me how popular these people really were.