A service to resist on-line surveillance
From the post, why end-to-end encryption is not enough: “End-to-end encryption has become more commonplace with major online messaging and communication tools, but encoding what you say to your friends online does not mean that the service provider cannot see who you contacted, when, from where. This metadata might be even more important than the content of an online conversation.”
https://nlnet.nl/project/katzenpost/
You have to think about the metadata in the same way we think about how services like Facebook develop “graphs” of us for the purposes of advertising and scores.