Online community is having growing social and commercial impact on the WWW, but what does “community” mean online? Can the level of community be measured? This article articulates an evidential conceptual model of community synthesizing earlier definitions drawn from the literature and creating new core conditions. The four conditions, purpose, commitment, context and infrastructure, we believe are necessary and sufficient for modeling and gauging intra-community “glue”, and that without this glue sustainable community cannot manifest.