Besides the unfortunate load issues Cuil is experiencing today (the engine opened to the public today), the launch begs the question of whether search relevancy alone is all you need to beat the search giant. If that was the case, we imagine Microsoft wouldn't have been as eager to acquire Yahoo, since MSN Search results already come close enough to its competitors. We tend to believe it's other factors like a well established visitor base and a powerful ad platform that were the major drivers in the failed multi-billionaire acquisition.
But please don't misjudge us, we are all for innovation and as much as we like Google, we are already looking forward the web's next big thing. Cuil, however, seems to be too much of an empty promise to become just that.