I for one don't understand the joke - maybe I'm
just a humourless old bastard,
The joke is that he offered, if we put in signature subkeys to stop
using V3 keys, and I complied.
The joke is that I don't *really* expect him to give up his V3 key.
Ian, I think you're doing the right thing not supporting V3 keys.
The biggest flaw in PGP 2 is that it is not fatally flawed. If there
were some horrible bug in PGP 2, we could all demand that people give
up their V3 keys, and even just drop them. Alas, PGP 2 is indeed pretty
good, and therefore it is hard to get people who believe it to be
divine revealed wisdom to change their mind; we can only tease them
until they get tired of hearing it.
Future protocol designers should learn from this experience and make
sure that their early revisions have some massive security flaw so that
it's easier to get people to upgrade to the revised version.