What is Usability?

Usability is the study of how at ease people use a certain product or how user-friendly for people to interact with a certain software or object. Usability testing usually involves a systematic observation under controlled conditions to see how well the person uses the product. For example, mapquest.com is used by a variety of people, old or young, to look up directions on the internet. The site is user-friendly and it is easy to use. It also offers choices in the vicinity so one could pick to be closer to the target requested. Another similar site is googleearth.com in which one could navigate the control as if one is flying the jet to zero in the target and to see the street views, buildings, houses, and so many interesting sites. The pictures are not up-to-date, but each picture is worth "a thousand words."