A button is something you touch or push to make something do something. I feel like in this time with so much emerging technology the design of a button is very important as is the design of the entire website to maintain a businesses image and perceived quality. It is very obvious when you come across an old or outdated website with design similar to websites of the 90s and it definitely changes the way I think of the company. Buttons now-a-days usually have a 3D look with a glossy finish to make the button look modern and realistic.
Great buttons in history...the one that comes to mind is the "LIKE" button on facebook! Everyone knows what it is because there are over 500 million people using facebook. I always see business ads on facebook saying ".."LIKE" this ad to receive coupons" or something like that and we automatically know what it is. You also see facebook "like" buttons on many other websites besides facebook so you can "like" the website and it will publish to your facebook for your friends to see (free advertisment for the website!).