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

[Ben Tilly]

On 9/9/05, Alex Bligh <alex at alex.org.uk> wrote:
> 
> 
> --On 09 September 2005 10:36 +1000 Brendan Scott <lists at opensourcelaw.biz>
> wrote:
> 
> > So I will further refine that last email to be AU specific
> 
> On AU law I cannot comment and I will thus bow to your knowledge.
> 
> > The question is whether the *mere presence* of a contract renders the
> > licence irrevocable - which to me overstates the case.
> 
> I think (and this is from memory) it's the presence of consideration, rather
> than contract per-se, that makes the license irrevocable in more recent
> judgments, though saying that I haven't got my hand on case-law, nor
> can I see anything but a technical difference between the two. I *think*
> (and I am equally unqualified to comment on US law) USC makes similar
> provisions for gratuitous licenses and that means "without consideration".
[...]

Out of curiousity, what happens someone revokes a license and that
revocation is OK in their jurisdiction, but not the jurisdiction that
a user of their software happens to be living in?  As a US resident
this would be particularly interesting for me if the US courts think
that copyright licenses are always unrevokable.

Out of further curiousity, "the presence of consideration" is a term
that I'd have trouble accurately interpreting.  For instance could
there be consideration with the GPL because one has the potential of
getting back improvements (even though there is obviously no
guarantee)?

Anyways, if I understand this conversation correctly, an open source
copyright license, once given, might be revokable.  However when it
may be revoked is fairly unclear, and is likely to vary by
jurisdiction.  It also doesn't seem to be a well discussed topic.  Is
that impression accurate?

Thanks,
Ben