On Fri, 21 May 2010 20:56:36 -0700, Nobody wrote:

But they can be cancelled if the news server permits, so not everyone
gets to read the original.

You'd hafta be VERY FAST.

My response to that above was posted in nano-seconds...

Er, you might THINK you're deleting a posted Usenet message to The
Whole Wide World, but in effect, all you're doing is removing that
posting from "your own news reader", that is, on your own PC.

IF (take note of the command), you unsubscribe from the ... (news
group de jour) and then RE-SUBSCRIBE/RE-JOIN, you'll quickly discover
that any supposed "deleted" messages are, flipping heck, still there
and the world is looking at them.

Absolutely, positively guaranteed.

Thank you for your expert advice. Now read what I said.

I never said messages can be deleted. The Cancel protocol has been a
feature of Usenet from early days. Because of abuse, not all news
servers honour requests so messages can be left on servers. Some news
servers do cancel messages, so my comment "not everyone gets to read
the original" stands.

RFC1036:
3.1. Cancel
cancel Message-ID

If a message with the given Message-ID is present on the local
system, the message is cancelled. This mechanism allows a user to
cancel a message after the message has been distributed over the
network.

YATPICMFP?