This study explores a user-centered approach to the comparative evaluation of the Web search tool ProThes against popular all-purpose search engines Yandex and Google. An original research design was developed. Data were collected from 12 volunteers who performed 48 search tasks in total. Main outcomes include: (1) search strategy supported through ProThes can be quite effective for focused Web search and (2) ProThes’ interface and system performance must be improved.The research was supported in part by the Russian Fund of Basic Research, grant # 03-07-90342
