Abstract This research aimed to investigate what role heavy users attribute to the Professional Technology Temple (PTT) Bulletin Board Service (BBS) article commendation and criticism (ACAC) scheme, especially in terms of discussion and knowledge construction. Data collection took place through a structured questionnaire anonymously administered to 120 heavy users as well as text analysis of the ACAC scheme usage for the two most frequented boards by these heavy users during a one-week time period. The construct of students' perceptions of the ACAC scheme was ensured through factor analysis and reliability analysis. The three factors were extracted including Knowledge Integration, Knowledge Sharing, and Participation. The ACAC scheme usage for the non-academic “gossip” board was much higher than that of the academic “education” board. Questionnaire responses by Taiwanese college student heavy users accessing BBSs mainly for non-academic purposes were found to be significantly different than those of the other four between subject groups including work, academic, and both academic and non-academic. Interpretations of these findings are given and their pedagogical implications are discussed.