When can licenses be revoked? (was: License Proliferation)

[Wilson, Andrew]

Ben Tilly wrote: 

> I didn't know, but it was my impression that it couldn't happen. 
> However when I googled for the topic, I found nothing saying that it
> couldn't happen, and http://www.ilaw.com.au/public/licencearticle.html
> saying that it definitely could.

> Is this really true?  And if so, does anyone have any thoughts on why
> it isn't more often discussed?

It may not be discussed more often because it may not be true.

I think Mr. Malcolm, author of the article you cite,
can find others who agree that contracts are, generally speaking,
preferable to licenses (cue Larry Rosen).  He may have much more
difficulty finding others who agree that open source licenses can
simply be terminated by notifying licensees. I am not a lawyer; 
the lawyers who frequent this list may want to comment. 

You can certainly find
historical cases of copyright holders who relicensed open source
software under proprietary terms and then ceased distributing
the open source version.  However, I'm not aware of any copyright
holders who then took the extra, drastic step of informing licensees
that
their open source license had been revoked.  You would think that
such a scenario would produce a big, public fight and that it would be
well
known if such a case had in fact ever occurred.

Andy Wilson
Intel Open Source Technology Center