Jute ribbon is just cross woven jute/burlap strapping. It's made in various widths. I use it for straps on my burlap foraging sacks. It can be found in most craft stores. It varies greatly in density/threads per inch and overall quality.
I think its benefits would be minimal on a bow. Surely it would help protect a bow's back from scrapes and dings, but I don't think it would hold down a splinter as well as a rawhide backing. In general, it seems light and relatively strong and I'm guessing it would be a better thing to back a bow with than some of the things I've seen used.