You seem to be using a different definition of "usability" to most of us throughout this discussion. To people like Nielsen (who certainly popularised and arguably originated the term) usability is like a science: it is about measuring how people behave in practice and improving your product in light of that hard data. Once may draw inferences from that data, if patterns start to emerge where some practices are on balance superior to others, but just as in science, such inferences are falsifiable and only as good as the latest data set.
It is more than a little ironic that useit.com itself has become less usable over time, according to many of the very factors that Nielsen himself has commented on in the past...
You seem to be using a different definition of "usability" to most of us throughout this discussion. To people like Nielsen (who certainly popularised and arguably originated the term) usability is like a science: it is about measuring how people behave in practice and improving your product in light of that hard data. Once may draw inferences from that data, if patterns start to emerge where some practices are on balance superior to others, but just as in science, such inferences are falsifiable and only as good as the latest data set.
It is more than a little ironic that useit.com itself has become less usable over time, according to many of the very factors that Nielsen himself has commented on in the past...