The concept of the ”I’m feeling lucky” button has always been very simple. When a user typed in a search query on Google and clicked on the button, it would take them to the page listed on the top of the results!
The idea behind the button was that a user would have to have a dose of confidence that they would be directed to the exact page they were thinking of, or at least a relevant one, in a single try. In other words they would have to feel pretty lucky – hence how the button got it’s name.
On the other hand, ”I’m Feeling Lucky” has also been labeled as a display of Google’s own confidence – that they can take you to the desired page in one try! Today, the way the ”I’m Feeling Lucky” button works depends on a feature called ”Google Instant”. When Google Instant is enabled and working, you really have no time to click on the button, as you start seeing suggestions and results the moment you begin typing a query.
However, if you hover over a suggestion beneath the search box, the ”I’m Feeling Lucky” feature will appear to the right! When Google Instant is disabled the ”I’m Feeling Lucky” button goes back to normal, and behaves the way it previously did! But whether Google instant is enabled or disabled, clicking on the button while the search box is empty always takes the user to the Google Doodles gallery.
The video below elaborates further on the same.