Outlook has this sort of thing, but the receiver sees the notification and has to accept it. Which is always a clear sign to me that someone sent something out and then thought better of it, so I always look extra-closely at the email in question.

Anyway, if people didn't accidentally send stuff like this, cnn.com and other mainstream media couldn't write an article about it every 6 months.

Some clients (e.g. Outlook) let you put a delay on your outgoing email, so you can cancel it if you change your mind in time.

And the email recall feature of Outlook/Exchange is also quite good. It even tells you how many emails couldn't be recalled (because people have already read them). It will only work within an organisation though, as it is a feature of the Exchange server.

I'd welcome an outbound mail queue in gmail (or whatever web mail provider is your favorite). Preferably one with some configuration options. In my case, I might have a default delay of 2 minutes or so. For more uncertain messages, I might bump their individual delay out to some hours.

This allows for alteration of a message that has not yet made it off the queue. But it has the advantage over e.g. a draft message in that, if circumstances do not change, no further action is required.

If a queued email bothers you enough, you can go back in and change it. But you don't have to remember the things that end up not bothering you; they will be sent after their delay expires. This works in concert with the natural flow of your attention, rather than requiring you to keep track of and follow up on draft emails whose topics your mind has decided it is no longer worried about.

It can also be used to email yourself, or others, reminders at a pre-determined time.

I imagine one reason gmail, for example, does not add such a feature is all the potential avenues of abuse. Accounts set up with to spam without further sign on, or to harass someone else. Or just the person who ueber-automates every moment of their day with umpteen bazillion delayed messages in the latest GTD meme. Google may have better uses for its electrons.

Plus... If its automated, you're not looking at ads while it's sent.

While it's not impossible, email just does not work that way. Email has no sense of state on the other end of a message. The extent of the feedback it gets is a bounce that may or may not have a descriptive error attached to it. Some systems could implement a recall option (Exchange may allow this, but I'm far from an expert) if the accounts are housed in the same system, but it is rarely done as it is against the stateless aspect. Email as a protocol(s) is very simplistic, which is why spam and spoofing are so prevalent. There is little room to have complex extensions on top of the existing system.

If, say, gmail implemented this, it would likely require an ACL from the receiving user that specified senders that were allowed to recall.

At one time or another, we've all accidentally sent an e-mail, probably by invoking the keyboard shortcut.

I would definitely be waiting to have my emails delayed a few seconds if Gmail would momentarily display an Undo option. This would mean that the email wouldn't even be sent until after the Undo option expired, so we wouldn't need to worry about the email protocol.

Yes, having "unsend" as part of the mail client functionality is the way to go.

Maybe the "send the message right now this exact millisecond" function should require an extra step from the user. And the default action should be to enqueue the outgoing messages and wait for N seconds/minutes before sending them.

And add some rule-based "are you sure you want to send this?" function since you are at it.

We are talking about a completely different thing now. Adding a delay or an Are you sure? confirmation is trivial but hardly solves the issue of regretting sending something intentionally.

in my opinion, no. it raises a lot of concerns about misuse.