Zooniverse is a multi-project platform for online citizen science projects, a well-regarded way of solving tasks by support of a large group of human participants, which are too complex for today's purely computational systems. But citizen science is not a game. A number of serendipitous citizen-led discoveries led to scientific insight the projects never planned to achieve. Source for these discoveries were discussion forums, which were used by the participants in an autonomous fashion to discuss 'interesting things' beyond the pure crowdsourcing workflow. This presentation is about the results of a broad study of the community and content dynamics on the Zooniverse platform, the first study of that kind, focusing multiple projects and the emergent cross-project effects.