INTRODUCTION

Data gathering and evaluation activities that aim to understand the users' point of view and their experiences when using a technology are a central element of user-centered design approaches such as Participatory Design and play a key role in the assurance of optimal user experiences (Douglas et al., 1993).

Identifying appropriate requirements to make interactive systems accessible is not enough to ensure the relevance and personal satisfaction of the designed system for users. "Designers need more soft data about users such as they problems, preferences, lifestyles and aspirations" (Newel, 2006, p. 112). Traditional data gathering and evaluation methodologies such as focus groups, interviews, observation, usability labs, and expert based evaluation (e.g., heuristic evaluation) together with new experimental techniques such as in-situ evaluation (e.g., living labs, observation, and mobile probes) can help to understand the user experience in the people's real contexts (for example, in their homes, at work, and on the move). At the same time, these techniques can be useful to identify design requirements and to assess the usage quality of the proposed applications and interfaces in terms of usability, accessibility, and last but not least, acceptance. Data gathering and evaluation activities need to assess specific experience of the users in their specific physical, system, and social context (e.g., community aspects in daily life, social cohesion, and social identity), in diverse situations and circumstances (e.g., leisure, government, and health care). At the same time it is crucial to verify the overall user acceptance of the applications proposed (e.g., using models such as the uses and gratifications).