Fieldwork Topic - Klezmer Band

I've decided to study the klezmer band at Brown, Yarmulkazi.  Part of my interest is that I've never studied (or really listened to) any music of this genre.  Perhaps a more traditional background would be best before I listen to Yarmulkazi, including listening to some recordings and reading about klezmer music.  

The klezmer band at Brown, Yarmulkazi, describes itself as playing "traditional klezmer (Eastern European Jewish folk music) as well as modern interpretations including klezmer-jazz and klezmer-rock fusion."   This description immediately reminded me of the Mauvais Sort YouTube video.  Yarmulkazi raises questions associated with 'tradition'.  What exactly is there tradition?  Is this music secular?  Is it founded upon liturgical roots?  Is the music, as interpreted by Brown's Klezmer band, in the same style as 'traditional' klezmer music, or is there a discontinuity?  

I hope to be able to answer those questions as well as come up with new ones.