There is a mechanism to send cancel and supercede messages, but due to
widespread abuse of the system it is almost never honoured these days, and
stands no chance deleting the message from more than a tiny fraction of
servers, never mind all the copies stored on individual users machines.

When you 'delete' from google, the only affect is google wont find it for you
any more. Its not even certain google deletes it from its internal database,
it doesn't when you deleted your email if you are foolish enough to use the
insidious gmail service, it continues to be used to profile you and anyone
who sends email to you.

---druck