Eric Chadbourne is a user on infosec.exchange. You can follow them or interact with them if you have an account anywhere in the fediverse.
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Gmail's upcoming self-destructing emails will require the recipients to click on a link and log in with their #Google accounts to see the content, if they are accessing via IMAP/SMTP.
Don't be fooled: Google's purpose is not to give us more confidentiality. They want all of their users to access their mailboxes via the Gmail app or their web interface, so they are creating a burden to the recipients and calling it “security” to convince people to adopt it.
Not sure how else #google could implement self destruction without users being on the same platform. I believe this is how #protonmail does it as well.
@miramarco
I doubt the utility of such a feature.
I also don't doubt your point on this is more marketing than security.