The process of analyzing and using information is often collaborative in nature especially given the broad and multi-disciplinary tasks that we must support today. Collaboration requires people to share "common ground", which is the knowledge that enables them to communicate and, more generally, to coordinate their activities. Common ground has been explored in a variety of systems, domains, and disciplines. Of particular interest are the new developments in online social environments (instant messaging, SMS, multi-player virtual worlds) that have become quite popular. Collaborative information visualization environments can benefit from common ground advances that are not only in the collaborative visualization area but also from advances in online social environments. In this paper we expand the notion of common ground for visualization systems based on our experiences with two systems we have developed. CoMotion is a collaborative information visualization environment. Reality Instant Messaging is a system that provides lessons from new interactive online social environments.