1: Anything that's federated is public (to instance admins) and can't be reliably deleted.
For ActivityPub, that's pretty much everything except user account.
For email (SMTP) that's sender, recipient, subject, and usually body.
Etc. Instance admins can log whatever they want. Laws like the GDPR or CCPA don't apply to all instances.
2: User signup is much harder because choice paralysis over which instance to join often sets in. That in turn leads to default recommendations, resulting in centralization in a few instances. E.g. lemmy.world, beehaw.org, sh.itjust.works, lemmy.ml for lemmy, Gmail, Apple mail, MS Live email, AWS email options for email.
1: Anything that's federated is public (to instance admins) and can't be reliably deleted.
For ActivityPub, that's pretty much everything except user account.
For email (SMTP) that's sender, recipient, subject, and usually body.
Etc. Instance admins can log whatever they want. Laws like the GDPR or CCPA don't apply to all instances.
2: User signup is much harder because choice paralysis over which instance to join often sets in. That in turn leads to default recommendations, resulting in centralization in a few instances. E.g. lemmy.world, beehaw.org, sh.itjust.works, lemmy.ml for lemmy, Gmail, Apple mail, MS Live email, AWS email options for email.