[username111]

Gmail has it as an option (labs last I used gmail), that is the best way I think to do it.

I don't ever find a need to undo an email though.

I believe it was only for like 20-30 seconds as well that it offered undo.

[pyre]

  | Gmail has it as an option

Supposedly Gmail added this as an option because their infrastructure was setup in such a way that the delay was already there. They just made hooks so that you could cancel it before it was sent.

[Intermernet]

Any chance you could hunt down a reference for this? I regularly test email servers from my Gmail account (amongst others) and I've found that their outgoing messages hit my mail servers almost instantly.