And SPDY is well documented. Everyone can implement it, even IE if they wanted. Microsoft has a knack for keeping the internal workings of protocols and file formats a secret, or at least very ambigiously documented.
I'm sure it was independently thought of by many people (me not included; I read it years and years ago...). Can't remember from whom, or if it was attributed at all. It has, to me, the feel of a Henry Spencer-ism.