The distinction between albino and hybino is indeed less dark pigment in the latter. "Hypo" and the twice-abbreviated "Hy" before "bino" are abbreviations for "hypomelanistic," where hypo = less and melanin = dark pigment, thus, less dark pigment
Hypomelanism is a line bred trait, that, as fattiesnleos mentions, promotes fewer black/dark brown spots. A line bred trait is one that cannot be bred all one way or the other, but rather, oscillates from less to more (here, dark pigment - spots). Taken to the extreme, hypomelanism can result in a complete lack of dark pigment. Hypomelanism seems to run hand-in-hand with yellow pigment filling in some to much of the light bands, but I don't know whether or not this is independent of reduced spotting (ever seen a gecko without spots, but with light bands? ) .
Suffice it to say, hybinos ideally have more noticeable yellow due to a lack/absence of dark (in albinos, brown) pigment. Shrunken or filled-in bands are also usually stipulated for hybinos (again, is this characteristic coupled with hypomelanism? ). Both of these characteristics happen with age - dark pigment takes a little while to come in, and bands don't fill with yellow overnight.
The common stipulation for more INTENSE yellow in hybinos seems inappropriate, since you can get brighter yellow in banded albinos, too. As we can see from non-albino hypomelanistic geckos (many of the SHTCHTHTCH-whatevers out there), the amount of spotting seems to be independent of the intensity of the yellow. You can have heavily spotted, very orange geckos, or you can have near-spotless, very pastey geckos.