Back in the days of FidoNet, people used Offline Mail Readers to batch-download new messages in their areas of interest, read and contributed over a few days and uploaded their responses when getting the next download. There was therefore a built-in cooling off period for hot messages - a chance to go back to your vitriol before you uploaded it and water it down or even delete it. It was a side-effect a lot of people appreciated.

Nowadays email is too instant and it is too easy to send things better left to render down for a while, as it were.

Wade.