I wouldn't be surprised if a term like the following is necessary.

> you represent having the right to grant, and you grant to the server operator, at minimum, an irrevokable, worldwide, royalty-free, sublicensable license to store, copy, perform, transmit, and transform, with attribution, and with sublicenses surviving such revokation as may be agreed by us, to the limited extent necessary in order to do the foregoing, your works made as messages in Mastodon in connection with the limited purposes of fulfilling the technical intent of Mastodon (which is the provision of a federated social medium, including the display of public, unlisted, followers-only and private messages to their intended recipients, who may be on other servers). the service may at its sole discretion, and generally will, offer a «delete» facility, which, if available, will make the best effort technically reasonable to communicate the deletion to all servers which have received your message. your use of the deletion facility severs our direct right to store, copy, perform, transmit and transform your message, and instructs us to revoke the license we give (which survives your termination of our direct license), as a consequence of the provision of a federated social medium, to other servers, which revokation they may not receive due to reasons outside of our control. your use of the deletion facility does not sever the sublicenses to other servers.