START. 15 years ago this button gets introduced to the Windows GUI. It will be the start of 15 years (or more years) of clicking this button. It had several transformations, from redesigning it with an eye candy look, just leaving the logo, and making the logo button a little bigger. Even with these changes, the fact remains is that it became Microsoft Window's trade mark. It was to become the distinction of the Windows' GUI from the Mac's. And people started learning and getting comfortable with this button.
