Virtual microscopes are commonly used in medical education. They provide a platform for distributing whole slide images (WSI) with several GB size to exploring students. Even in courses with a few hundred students and dozens of WSI the network traffic may be high, but it will vastly increase, when the system is opened to access from the Internet. The same applies to user-generated content like interactive annotations (each student generates approx. 200 labels per term). In a collection that consists of several thousand WSI, which need to be annotated for training or quiz-based purposes, there will be millions of user contributions. In an abstract view users navigate through a universe of WSI and annotations and may meet other users watching the same or related WSI. This paper presents a distributed architecture build on PathFinder for Internet-based virtual microscopy addressing the challenges of distributing tightly connected data chunks on an overlay network consisting of random graphs.