Quirky but not really correct. He thinks he is inventing new stuff, because he is ignorant about the science that's already been done, and he's probably kind of NPD so he never doubts or checks his ideas. Sorry if I seem harsh, but these pseudo-science types piss me off, because they waste people's time and try to agrandize themselves without doing anything real. Richard Feynmann or Niels Bohr are a thousand times more intersting than a guy with a crank website.
Quaternions are not "forgotten", they get used all the time. They've been used for decades in computer animation to represent rotational motion (that guy implies that is his idea, which it isn't). They, and the closely related Cayley-Klein parameters are a useful representation of solid-body rotations, the Lie Group SO(3). Other matrix groups like SU(2) are somewhat related and are important in quantum field theory. Here are some places to get started looking at the real thing:
Special Unitary Group:
http://mathworld.wolfram.com/SpecialUnitaryGroup.htmlQuaternions:
http://mathworld.wolfram.com/Quaternion.htmlGauge field theory:
http://en.wikipedia.org/wiki/SU(3)XSU(2)XU(1)SO(3) is called a "Lie Group" because the space of all solid-body rotations forms a 3D space, a smooth manifold. It has the same topology as projective space, but in addition it has a continuous group algebra superimposed on it (multiplication of rotation matrices). Field theories explore these and many other more exotic Lie Groups to see if their symmetries are the same as observed physical quantum fields. Guys playing with quanterions are lightyears behind the state of the art today...