Fascia is of huge importance. It is one of only 3 networks that run throughout the entire body, the other two being the fluid and neural network. Anything that the body considers important enough to weave into every orifice of the body is simply vital, otherwise evolution would have thrown it in the trash long before we even made it out of the cave. So if this fascia stuff is so important how come we know so little about it and what the hell does it do anyway?
I believe it stems from the way anatomy is currently thought in school. We see pretty pictures of a muscle connecting to a tendon which in turn attaches to a bone; three perfect structures independent of each other. The truth is that it's far more like a continuum, everything flows gracefully from one structure to the next and the thing that ties it all together is fascia. Fascia is a matrix of fibrous connective tissue that runs throughout the entire human body, separating and binding together muscles and organs. Chaitow describes fascia a little more eloquently in this awesome blog as an "elastic-plastic, gluey, component that invests, supports and separates, connects and divides, wraps and gives cohesion, to the rest of the body". It's like a 3-D cobweb, but can also function as a sheath to wrap structures. It's simply fascinating stuff, and with research currently exploding in this area we're learning that fascia has more functions than we ever thought possible. Without going into a review of the current literature it's safe to say that it's far from a background material.
Here is a superb video that will give you a better idea.