this paper compares 12 representative chinese and english online question-answering communities (q&a communities) based on their basic functions, interactive modes, and customized services. an empirical experiment from a comparative perspective was also conducted on them by using 12 questions representing for four types of questions, which are assigned evenly to three different subject fields so as to examine the task performance of these 12 selected online q&a communities. our goal was to evaluate those online q&a communities in terms of their quality and efficiency for answering questions posed to them. it was hoped that our empirical research would yield greater understanding and insights to the working intricacy of these online q&a communities and hence their possible further improvement.