at the bottom of this page the NURBS Weights are set to: TODO
https://www.blender.org/manual/modeling/curves/introduction.html
I did a little digging and found out it is for "Soft Body Goal"
"Soft Body Goal acts like a pin on a chosen set of vertices; controlling how much of an effect soft body has on them. "
"A Soft Body in general, is a simulation of a soft or rigid deformable object."
https://www.blender.org/manual/physics/soft_body/reference.html
https://www.blender.org/manual/physics/soft_body/introduction.html