It seems to me that the DAO is a large enough player in the Ethereum community that this plan is likely to succeed. If it does, it will be the first example I know of where a 51% attack was successfully executed against a popular blockchain.
Whether or not this is a desirable thing depends on your goals. From the perspective of the Ethereum community, which is heavily invested in the DAO, it makes a lot of sense. Even if this vulnerability causes you to write off the DAO as a failed experiment, it makes sense to recover some of your lost value before you exit.
However, for my goals, this causes me to write off Ethereum as a cryptocurrency I will never, ever use. It's breaking the fundamental benefits of the cryptocurrency to fix the problems of one group. And further, if this is possible for Ethereum, it makes me think that a 51% attack is more plausible for other cryptocurrencies. This worries me. I'd like to see more research put into defending against 51% attacks.
> On August 15 2010, it was discovered that block 74638 contained a transaction that created over 184 billion bitcoins for two different addresses. This was possible because the code used for checking transactions before including them in a block didn't account for the case of outputs so large that they overflowed when summed. A new version was published within a few hours of the discovery. The block chain had to be forked. Although many unpatched nodes continued to build on the "bad" block chain, the "good" block chain overtook it at a block height of 74691. The bad transaction no longer exists for people using the longest chain.
While this does demonstrate a 51% attack, I think there's a key difference here. With the 2010 Bitcoin fork, the problem was a bug in the core infrastructure which was broken. The 51% attack broke the core infrastructure, but that core infrastructure was already broken. In that case it was a matter of choosing which way the core infrastructure breaks.
In the current Ethereum situation, the core Ethereum infrastructure isn't broken. The problem is with the contracts in the DAO. So creating an intentional fork is breaking the core infrastructure--which isn't broken--to fix the problem of a single majority stakeholder.
I don't mean to indicate the Bitcoin fork wasn't a problem--the fact that bugs can break core infrastructure also concerns me. But it's a very different problem from the one the DAO is creating here.
Whether or not this is a desirable thing depends on your goals. From the perspective of the Ethereum community, which is heavily invested in the DAO, it makes a lot of sense. Even if this vulnerability causes you to write off the DAO as a failed experiment, it makes sense to recover some of your lost value before you exit.
However, for my goals, this causes me to write off Ethereum as a cryptocurrency I will never, ever use. It's breaking the fundamental benefits of the cryptocurrency to fix the problems of one group. And further, if this is possible for Ethereum, it makes me think that a 51% attack is more plausible for other cryptocurrencies. This worries me. I'd like to see more research put into defending against 51% attacks.