The Washington Post has a nice article on Google's "I'm Feeling Lucky" button. Even though fewer than one percent of Google searchers use the button, Google refuses to remove it.
Marissa Mayer, vice president for search products and user experience, said "If we took it away, there would be mass protests worldwide."
I believe it, I really do. The article says that "Google loyalists" get the impression from the button a "touch of whimsy and reassurance that the company doesn't take itself too seriously." This may explain why Google has on many of their contextual ads, the line, "Ads by Goooooooooogle."