Looks like they are just adding a planer parabolic reflector behind an existing vertical antenna element, nothing profound, just a simplification of a parabolic dish. Still, for indoor use, it is a neat idea. For outdoor antennas, you would want more durable materials, but no reason it would not work where only modest gain was needed. Not sure how it would compare w/ a straight reflector (i.e. a 2 element yagi).
Another interesting antenna for for WiFi are the Pringles can antennas.