[BlackForestBoy]

Oliver here, from the Memex team.

Up until now all data is stored on your own device, or in your personal cloud with a file system integration (like a Dropbox folder)

We are about to release our mobile apps for iOS and Android, as well as syncing between devices. Both the extension and mobile app will be offline first and sync happens with an end2end encryption via a relay server that deletes all messages after all devices have been picking them up. That server will in the mid-term be self-hostable too.