A system to design, create integrate and operate online communities uses web-based participation technologies. Any content can have attributes that make it appear as any type of content. With this uniform content architecture, all user-generated content is treated as a post (or, more generally, a submission), and there is no need for a participant to author multiple entries for separate uses. Preferably, content created or otherwise associated with a particular author is intrinsically tied to the author via the author's profile. At each point of participation, the content is associated with the individual, which allows the system to build and maintain a rich “living” profile for each community member. Using this approach, the system can build and enable querying of so-called “social aggregations,” which are data sets that describe a relationship among one or more author attributes and one or more content attributes.