Abstract Online communities have become a key source of information and support. These communities enable Wikipedia users and contributors to coordinate their activites, patients to cope better with their diseases, students to discuss homework projects, hobbyists to pursue their passions, and teens to chat about their lives. Scholars use online communities to track academic topics, lawyers seek legal information, and professionals exchange business knowledge. A variety of software facilitates information exchange and communication including: wikis, blogs, discussion boards, instant messaging, and immersive virtual environments. In this talk I will discuss the concept of an online community, review my research terrain and briefly present some findings, for example: a framework for developing and analyzing online communities, and results from studies about empathy, information exchange, and why people often observe but do not actively contribute (i.e., ?lurk?) online. Empathy, information exchange, and behavior online varies between communities. In one study, for example, we found strong differences in the amount of lurking in patient support communities compared with technical support communities. Analysis of survey responses from 219 observers revealed reasons for lurking that included: wanting to learn more about the community, intending to be helpful, poor usability, poor group dynamics, and desire to take without giving back. Based on our findings, we proposed changes in social management and information architecture to encourage participation, support empathy between participants, and facilitate information seeking and browsing. Finally, I will suggest future research and development directions for encouraging community activities associated with Wikipedia. -- http://wikimania2006.wikimedia.org/wiki/Proceedings:JP1 Less