Dwayne wrote in
.net:

BTW if the message that you posted makes it to other newsgroup
servers before you deleted it then it will still show up. There
is no way that you can completely delete a post.


That's not true, the cancel request would be processed just like any
other message. Whether other servers around the world would honor
such a request is another thing.

As for being stored on local computers, that would depend on
individual configurations. Some folks may store full messages, other
only headers for the groups that interest them....

--
You are a fluke of the Universe
You have no right to be here
And whether you can hear it or not,
the Universe is laughing behind your back