It sounds simple — when crafting an email, you can make it “confidential” (only for the recipient) and/or self-destructing (expiring after a given period and not readable after that). Instead of a normal SMTP email message wafting off into the ether, an email is sent with a link to a secret page where the recipient, once they prove who they are, can see the message (but not copy it!) until it expires and is taken down.
Sounds clever, but it’s really not.
First off, the idea that nobody will be able to copy or otherwise save the email is just plain false. It sounds like copy-paste is disabled, but not screen capture. Heck, just use your phone to take a picture of it. Silliness.
Second, the validation process (proving you are the intended recipient of the confidential email) sounds a bit onerous — responding to a text message, logging in, etc.
Lastly, this sound like a fabulous way of generating malware infections. Miscreants can send someone a message with a faked sender (easy), the standard confidential Gmail link text (easy), and a link that takes you somewhere bad (easy). How will you know it’s a trap until you’ve sprung it?
Not all that confidential, inconvenient, and possibly dangerous. Hmmm. Yeah, as it stands, I won’t be using this feature, and won’t be recommending it to any one else.
Google is testing self-destructing emails in new Gmail – TechCrunch
"This email will self-destruct in 10 seconds."
Alas, this is how Microsoft's version works, and Google need to offer it to stay in the commercial hunt.