The additional notes for the ISO definition explain that user experience includes all the users' emotions, beliefs, preferences, perceptions, physical and psychological responses, behaviours and accomplishments that occur before, during and after use. The notes also list the three factors that influence user experience: system, user and the context of use.

Note 3 of the standard hints that usability addresses aspects of user experience, e.g. "usability criteria can be used to assess aspects of user experience". Unfortunately, the standard does not go further in clarifying the relation between user experience and usability. Clearly, the two are overlapping concepts, with usability including pragmatic aspects (getting a task done) and user experience focusing on users’ feelings stemming both from pragmatic and hedonic aspects of the system.

In addition to the ISO standard, there exist several other definitions for user experience. Some of them have been studied by Law et al. (2009).

The term user experience was brought to wider knowledge by Donald Norman, User Experience Architect, in the mid-1990s. Several developments affected the rise of interest in the user experience:

The field of user experience was established to cover the holistic perspective to how a person feels about using a system. The focus is on pleasure and value rather than on performance. The exact definition, framework, and elements of user experience are still evolving.

A diversity of things can influence a person's user experience with a system. To address the variety, factors influencing user experience have been classified into three main categories: user's state, system properties, and context (situation). Studying typical users and contexts helps designing the system. These categories also help identify the reasons for a certain experience.

The three main user-experience factors are best illustrated by a scenario below.

Lisa is on her way home by bus, and wants to know how her husband is doing on a business trip. The bus is crowded and she did not get a seat, but she wants to use the time to contact her husband by phone. What affects her user experience with the mobile phone?

Depending on husband's messages, Lisa's emotions may range from delight to sorrow, from excitement to despair. User experience focuses, however, on Lisa's feelings about using the mobile phone, not about her husband. Did the system enable her to communicate with the husband in the way she wanted in this context? Did the system delight her by exceeding her expectations or by attracting positive reactions from others?

The scenario above describes user experience of communicating with a relative via text messaging with a mobile phone. We can investigate user experience on many temporal levels, however. In the scenario above, we could study Lisa's changing emotions during interaction, her feelings about the episode as a whole, or her attitude towards her phone in general, i.e., her overall UX. In the above example, focusing on the momentary emotions may not be the best way to understand Lisa's user experience, since her emotions were caused mainly by the content (the messages from Lisa's husband) and not by the examined system (mobile phone). However, in systems where the content has the primary focus, such as in electronic games, the flow of emotions may be the best way to evaluate user experience.