This should be a part of the process of ALL sites that use email/domain ownership as proof of identity. There are a lot of them besides Facebook. Yeah, it's no

This should be a part of the process of ALL sites that use email/domain ownership as proof of identity. There are a lot of them besides Facebook. Yeah, it's not currently possible for phone numbers, but that's not a reason for not doing it for domains where it is possible. It's also easy to imagine a privacy-respecting public registry for phone numbers, which only reported when the ownership had changed.