Interestingly, Marketing guru Martin Lindstrom talks about the limits of most testing methodologies, opting for fMRI scans (functional Magnetic Resonance Imaging) as the most conclusive means of understanding why people are engaged in just about anything. Perhaps this is the future of usability testing?

Note, however, that user-centered design methods quickly moved beyond this to encompass techniques providing a broader view, including social and environmental factors. Ethnographic methods and diary studies, for instance, can help uncover some of the identify construction and social engagement qualities of online interaction.

The term “user experience” is often used instead of “usability” because people have a broader set of concerns in view. So the question is not just “can I get done what I need to do” but also “am I enjoying this enough to keep doing it.” There are methods and practitioners out there that do this well. But it tends not to be called usability.