Gmail labs has implemented a feature called “Undo Send.” It’s described as Oops, hit “Send” too soon? Stop messages from being sent for a few seconds after hitting the send button.

Frankly, I tried it and I was not impressed because the undo button is too small to be noticed. The description indicates a few seconds, in reality it’s around 5 seconds.

I’ve experimented by sending an e-mail to myself, while you’re deciding if you want to undo send, the e-mail has already arrived because Inbox (1) is shown. After pressing the undo button, the e-mail already in my inbox magically disappears!

You can enable the “Undo Send” feature by doing the following:

1. Go to your Gmail Settings.
2. Go to the Labs tab, scroll down and find Undo Send. Or simply press Ctrl-F to open your Find box and type in “Undo Send.”
3. Enable it by clicking the appropriate radio button.