Here's how the new Gmail's 'expiring emails' feature works

Gmail's massive redesign includes a feature that has previously only been available on corporate email services, encryption-oriented programs like ProtonMail and Signal, and, well, Snapchat: disappearing messages.

SEE ALSO: How to upgrade to Google's new Gmail right now

It's part of Gmail's new "confidential mode," which will supposedly give users an added layer of security when sending emails. This includes the ability to password protect emails, unsend messages, and prevent others from forwarding, printing, copying, or downloading messages. Disappearing messages come through the ability to set expiration dates for emails — which means they will "disappear" from inboxes after a specified amount of time.

Confidential mode will roll out "in the coming weeks," according to Google. But Mashable was curious about how well the self-destructing emails will actually work. Google suggests that (potentially incriminating, often innocuous) emails wouldn't be available to prying eyes in the future; that your email would not be a forever trove of every online communication you've ever had.

So, if people actually use expiration dates, they could prevent data dumps like those from the John Podesta hack, or lawyers' ability to get all email communications in lawsuit discovery, and use messages in incriminating ways, as in the Gawker lawsuit.

But do expiring emails actually achieve this panacea of online communication? Gmail shared a few more details about how it works. In short, this feature works well for the very specific instance of not letting a recipient see the email you've sent them after a certain amount of time, which is what Google explicitly intends it to do.

But does it have the ability to automatically wipe out all trace of the email from the interwebs, as the "confidential mode" and "expiring" labels might suggest?

Not so much.

How to set an expiration date

To set an expiration date in the new Gmail, you'll need to enable confidential mode on the specific email that you're sending. Click the little lock with a timer on it to the right of the send button in an email. Then you select the time period after which you want the email to expire.

The expiration occurs on the specific day set by the sender — it doesn't depend on when the recipient gets or opens the message.

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Credit: google

Where does it actually disappear from?

When emails expire, they disappear from the recipient's inbox or whatever folder it has been stored in on the recipient's end.

What about recipients who aren't on Gmail?

Here are details from Google about how it deals with disappearing emails for Gmail vs. non-Gmail users:

Gmail replaces the message body and any attachments with a link. Only the subject and link are sent via Simple Mail Transfer Protocol (SMTP) - an Internet standard for electronic mail (email) transmission.

If the recipient is a Gmail user, the message will render / appear like a normal message in Gmail. If the recipient is not using a native Gmail client or is on a different email provider, the confidential message will instead have an HTTPS link that directs the recipient to a Confidential Web Portal where he/she may securely read the message.

This means that, if you send an expiring email to a non-Gmail user, there will be a trace left that the email exists. The actual content will be gone, since it's stored (and deleted) elsewhere. But it definitely means that the feature doesn't wipe away all evidence that you've had communication with someone.

Do expiring emails disappear on the sender's end?

No. Expiring emails remain in the "Sent" folder. This means that people who use expiring emails should make sure to permanently delete folders in their sent folders, if they don't want any trace of them to exist.

As we see it, this is a pretty big shortcoming of the feature. A big perk of expiring messages is that purging happens automatically. If a message is only deleted on one end, an online record exists.

So if a message expires on the recipient's end, and is deleted on the sender's end, is it really... gone?

This is a tricky one. Google says, "when you delete a message, it stays in your Trash for 30 days. After that time, it will be permanently deleted from your account and can't be recovered."

This wording seems to specifically skirt the question of whether emails remain on Google's servers — and if so, for how long. Some past reports have said that deleted emails remain on Google's servers for 60 days after they disappear from Trash. We've asked Google for more clarity on how long it stores deleted emails on its servers.

Credit: giphy

All in all, "expiring emails" seems to work well if what you want to do is prevent an email recipient from seeing the content of your email after a specified amount of time (although, then again, nothing is screenshot-proof).

But it's neither a privacy guarantee, nor an all-purpose tool that automatically erases a record of your online conversations. For gmail, the cat might just be out of the bag on that goal.

UPDATE April 27, 2018 2:40 p.m. E.T.:Google sent us the following statement regarding how long deleted emails stay on Google servers:

We're not able to comment on internal procedures. 

CORRECTION April 27, 2018 5:30 p.m. E.T.:An earlier version of this story said that Google’s intention was to make emails "disappear." The article has been updated to reflect that the company never made this specific claim.

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