The content of "success" of an information system is good/positive experiences of targeted users.
Ends of system design are some types of user experience.
In this sense, 'personal' dimension is more important than the technological.
Thus, for a system installation, the system designer give a first priority to looking for value at the individual level, instead of attempting to demonstrate organization-wide value.
The key issue for designer is to notice/consider/understand 'personal' dimension.
The term "user experience" refers to a stance that places the end-user at the focal point of design in general, in particular information system design. It stands on the regret that "if we build it, they will come"-approach does not work.
The cocept of "user experience" is near to "user-centered". But, here "user-centered" should be understood in this way : User's needs/preference is not what is present now but is on the way of development toward a future - the designer contributes this development. Here the difficulty is to find an appropriate place between oposite poles of "pandering to popular tasts" and "designer's self-satisfaction". Indeed, the designers (diverse themselves about fields, such as developer, usability professional, designer, information architect) have their personal preferences (subjectivity) for types of user experience.
User experience is discribed/analyzed in terms of (1) user's trait (needs, motivation, inclination, capacity, resilience, etc.), (2) user's action/performance over the system (job content, quality of work life, etc.), and (3) user's satisfaction (job satisfaction, etc.).
And as the "user experience"-concerned characteristics of the information communication system (particularly the web-based one), we may use the followings and suchlike : (1) usability (about operation), (2) functionality, (3) contents.