actually, reverse scrolling is introduced in Mac's Lion OS. The reason they did that was mainly to transition people to get used to the scrolling of touch devices. this is also to turn the touch-pad on the mac like an "off-screen touch screen"
traditional wheel-scroll scrolls down to go down. on the otherhand, on a tablet or smartphones, you "flick up", "drag up" or "swipe up" the page to get to the bottom. the motion is synonymous with "scroll up" hence the reverse.
I heard this from Attack of the Show in G4TV when they reviewed an iMac with that type of scrolling. it's also explained in the Lion's new features under "Scroll direction preference"
not a bad idea for an OS, especially in the touch-screen era. but i don't know why they applied it in a website. just being different? being unique?