The site was only for putting the 6 key words in. You had to search the entire internet for the words, not the special page they made. It took people several hours to figure out the 5th word, and it did a good job of bringing people together to figure it out. Now that it has been figured out, I don't see the point in bringing people back to a page just to type in 6 words they can google
Having helped run some of these types of scavenger hunts myself, it's completely unavoidable and expected that fans will share the keywords with each other on Facebook, Twitter, message boards, etc., but when big sites link straight to the private Soundcloud player itself, I think that's a different story, and is worth trying to nip in the bud.
I don't know when this particular campaign was launched, but I'm guessing they at least want the illusion of a "scavenger hunt" to live for a day or two before making the stream publicly available to everyone.