Well, now everyone can calm down a bit because the countdown is over. So, what was the purpose? The purpose was to make you think there was a purpose. The folks at eon8 describe it like so:
The purpose of this project was to determine the reactions of the Internet public to lack of information. We were amazed to discover that the site was instantly linked with terrorism, simply for the fact that it seems mysterious. Evil was the number one first impression people had of the site, in spite of the fact that there are no threats on the site.
So, HA! Take that Internet and Halo 3 fanboys. You just got punk'd!