This website shows a map of reddit. Each dot is a subreddit. Two dots within the same cluster are usually close to each other if multiple users frequently leave comments on both subreddits
This website shows a map of GitHub. Each dot is a project. Two dots within the same cluster are usually close to each other if multiple users frequently gave starts to both projects
The Wikiverse project is an interactive 3D visualization of Wikipedia, reimagined as a cosmic web of knowledge. Here, articles are stars bound together to form topics, fields and subjects.