[Xurinos]

Every time I see the phrase "open source", I mentally add "but not open binary"; how do I know that the service that is run uses binaries that are compiled from that open source alone? with trusted libraries? After all, anyone can employ a site-specific patch in their build process that adds additional "features" to their normally open source project.

Is there a reasonable way to have trusted individuals intermittently audit the service?

[muyuu]

A no-trust-required system would consist of taking these sources and hosting your mail yourself. Which pretty much defeats the purpose, since what you want to avoid is hosting your own email (another alternative).

Honestly I lend more towards phasing out email completely. Maybe providing gateways to other protocols.