It's only the largest online scavenger hunt ever.
Unlock the achievement.com you can register to start searching. There are a ton of great sites including my own, GamingAngels. com that are part of this scavenger hunt. It's free to play, and you can win some awesome prizes. Also it gives you a chance to check out some new sites along the way.
The contest runs from today through Friday. So get started right away. Even if you don't find alot of clues, there are random winners being chosen every day.