As online communities become increasingly popular, researchers have tried to examine participating activities in online communities as well as how to sustain online communities. However, relatively few studies have tried to understand what kinds of participants constitute online communities. In this study, we try to contribute online community research by developing “common language” to classif...

Most research on supervised learning assumes the attributes of training and test examples are completely speciied. Real-world data, however, is often incomplete. This paper studies the task of learning to classify incomplete test examples, given incomplete (resp., complete) training data. We rst show that the performance task of classifying incomplete examples requires the use of default classi...