User experience design sometimes is a bit miss-leading （ or easy to lead
understanding ), this more or less leads by the name expanding tradition
(let's call it expand-ism), e.g. if we start from usability design, it is
being tried to cover as much topic as possible(on proof is the different
understanding of usibility design), as well, it's now seems happens on UX.
Besides, Alan Cooper gave a quite good reasoning on UX in his AF 2/3.0, UX
is something from the user, which be enabled instead of designed directly.
This is worth twice thinking. At the same time, IMHO, UX‘s gem may lies at
describing the quality of (interaction here) design (some people, as well as
myself, may prefer call the practice by its target problem domain instead of
quality description, but as previous described, there're different version
of UX from different understanding, :)).
[this thread is not intend to fire another naming war, :),
it'll definitely falls in vein by expand-ism ]