Information seeking is an dynamic and interactive process. Factors like users' information needs, individual differences, goals and tasks, knowledge and cognitive abilities etc. influence the information seeking process, and need to be identified and supported in the user interface design. We adopt a user-centered approach to establish a link between research within the IR interaction perspective and the methods in HCI on how to evaluate information seeking interaction in a hypertext IR system (Dienst). Our purpose with this exploratory study is to identify, describe and acquire knowledge of characteristics of the user population, and finally, to make suggestions for supporting users in user interface design. For the evaluation task, we have applied HCI evaluation techniques to our IR evaluation to make a connection between the traditional IR evaluation and HCI evaluation, combining different qualitative and quantitative data collection and analyzing methods, implemented in an experimental real-world online WWW setting. This methodology combined online (WWW-based) questionnaires and database log statistics. Preliminary results revealed several "hidden" realities: a mismatch between what people said they wanted to do as opposed to what they actually did. We also observed that people initially expected a specific function, but when using the system, they did not use it. Finally, we established some group differences concerning variables like previous experience searching information in hypertext systems, IR knowledge and browsing/searching strategies.