@cordlord120 @TheSwiv With all due respect, Matrix does not encrypt metadata at all (try "view source" on an encrypted message and read the unencrypted body). Therefore, if one is able to access your homeserver, then they can figure out who you talk with. Of course, it can be mitigated to some extent if everyone uses different homeservers (even better if it's bulletproof, but that's impractical) but currently matrix.org is effectively the default, so the risk is still there.

@alienghic @dartov I referred specifically to performance benefit. It might not apply to smaller homeservers, but the one I'm on (tchncs.de, one of the largest third-party public homeserver, yet it only has 3K active accounts) tried to enforce retention and gave up because running the purge job took out the homeserver... For media see https://github.com/element-hq/synapse/blob/master/docs/usage/configuration/config_documentation.md#media_retention .