On Wed, Mar 13, 2013 at 2:28 PM, Pieter Wuille <pieter.wuille@gmail.com>wrote:

> But we cannot just drop support for old nodes. It is completely
> unreasonable to put the
> _majority_ of the network on a fork, without even as much as a discussion
> about it.
> "Oh, you didn't get the memo? The rules implemented in your client are
> outdated." - that
> is not how Bitcoin works: the network defines the rules.
> ...
> Finally, we'll have to schedule a hard fork to drop the 0.8.1 limit. This
> is something
> that requires widespread community consensus - far more than just miners
> and developers


The way I've started thinking about it is that there is a market for
securing a payment network.  In that market you have consumers (users of
bitcoin) and providers (miners).  It's not clear to me that if the
overwhelming majority of miners stayed on 0.8 that the 0.7 fork wouldn't
have still won out in the long run because effectively what you would have
had is a situation where the providers abandon a large portion of their
customers (0.7 users) and start providing a service that is in much less
demand.  Would everyone have upgraded to 0.8?  Maybe, but maybe not.  Maybe
many people would have made the rational decision to stay on earlier
versions and the small minority of miners that choose to service the 0.7
fork could have earned more Bitcoin on that fork...and maybe in the long
run, the majority of miners on 0.8 would realize this situation and start
to trickle back over to the 0.7 fork.  The flip side of the equation is
that the users have a pretty compelling reasons to use the services of the
most secure network (less risk of double spends).  So, the users very well
could have made the rational decision to consume the services of the most
powerful network and made the switch to 0.8.

What happened in reality is that the majority of the mining community made
the rational decision to service the largest pool of customers (0.8 as well
as 0.7 and earlier users).  It was rational because the risk of servicing
only the 0.8 users would have been much greater.

Because of this dynamic, I doubt there would ever be multiple forks of any
consequence in permanent coexistence.  I would even go so far as to say
that at this point, a successful competitor to Bitcoin would have to arise
as a fork of the UTXOs in the block chain (even if the competitor didn't
even use a block chain).  That competitor might even have to begin life in
lock step co-existence with Bitcoin, recognizing all Bitcoin transactions
for some period of time while it attempts to gain market share.