Web site usability is task oriented, meaning that usability testing
measures the efficiency of how users (who fit a specific persona or
profile) complete a desired task. Testing is done one person at a time,
not as a group, and each participant's behavior and actions are
carefully observed and recorded. I have personally witnessed, countless
times, many participants say how beautiful they think a web site is and
subsequently never complete the desired task. I have observed many
participants say they will take one action and then do something else.
You can have the most beautiful, award-winning web site with top search
engine positions...and little or no conversions because the site just
is not user friendly.