 Which do you think is a superior platform for smart contracts? Bitcoin with sidechains like Ritstock, Ethereum, or one of the self-proplained 3G or third-generation blockchains? The problem is, you can't really compare these things. The reason you can't compare them is because one exists, and the other two are mostly roadmap or test software. Ethereum exists, and you can like it, hate it, but express an opinion as to how good it is for smart contracts, and what kind of problems it has, and how those problems are being addressed by the developers and community in Ethereum. I think they've done okay so far. Some big mistakes, some great successes, and the platform is gradually and slowly maturing. I'm interested in seeing how that goes. Until you have drivechains, Ritstock is a more centralized federated model. It would have to bootstrap some kind of consensus algorithm that's a bit more decentralized, and it's still in the very early stages of testing. It's promising, interesting, different, but not yet. The third-generation blockchains are suffering from the fact that most of them are not able to differentiate sufficiently with the first-generation blockchains, or second-generation blockchains. They are babies with big ambitions. When they grow up, we will see and judge according to scale. Do it at scale first. If you're not doing it at scale, you can't draw any conclusions. First, you have to put a big pot of money on the table and say, I'm going to secure this with a smart contract, let's see what happens. Sometimes what happens is millions of dollars get stolen or locked into a contract accidentally, but that's how you learn. That's how you find those blocks. Right now, the superior platform for smart contracts is really the only platform that's doing smart contracts at scale, which is Ethereum, and whether it's superior or not, that's a whole other discussion. What makes Ethereum interesting to you? What would you say to someone who thinks it's nothing more than an educational example of how not to do smart contracts? When I say Ethereum, I think I'm speaking a bit more broadly than the ETH token and blockchain. I'm talking more about a virtual machine-based, during-complete, programmable blockchain that allows you to run smart contracts. Which would encompass things like classic, rootstock, and possibly less than a few others. I find them all interesting. I think the idea of a general-purpose programmable blockchain, where you can run programs, as I hate the terms, more contracts honestly, but where you can run programs that are triggered by transactions and track the state, it's a difficult idea to execute on. It's going to take a long time to mature the security. Along the line, there are going to be a lot of mistakes, missteps, and burnt money, and crashes, and security vulnerabilities. But I think in the long run, something useful can emerge from that. There are some scaling issues, there are some security issues, but I think we'll see the maturity getting to the point where you can do interesting things. Interesting things that take the security flexibility trade-off that Bitcoin has made, slightly into the flexibility side, with still being able to maintain enough security to do some very interesting things that you cannot do with Bitcoin. There are things that you can do with Bitcoin. And doing those securely is very, very difficult. We've seen that again and again with Ethereum. Ethereum can do what Bitcoin does. I've talked about these trade-offs before. In fact, no turn-complete virtual machine-based blockchain can do what Bitcoin does. Having a script language that is very simple, not turn-complete, and very robust, I think is a very important differentiator, and it has certain very useful applications. I find Ethereum interesting as a platform for testing software engineering in the blockchain space, on a much more rapid basis than Bitcoin. Bitcoin, because of its nature as a robust reserve currency and very secure decentralized payment platform, has to be conservative. As a result, it has to move slowly, and it can take risks. There is no way that we could do proof-of-stake as an experiment on Bitcoin. They are about to do it on Ethereum. I am very interested in seeing how that experiment plays out. If it is successful, it will open the door for a lot more interesting consensus algorithms, hybrid systems, interactions between blockchains, and great development in the state of the art of science. All of those things make Ethereum interesting. I am interested because it can move faster. I am interested because it explores a much broader set of applications. I am interested because, despite its missteps, it has taught us a lot of useful lessons. We are learning a lot about governance as well. There are some very tricky questions about when do you fork? When do you not fork? Who do you bail out? Who do you not bail out? How important is immutability? All of these things are being experimented on because of Ethereum. I also like the fact that having other robust blockchains with strong valuations, liquidity, and lots of transactions, aside from Bitcoin, makes the space healthier for everyone. When Bitcoin is happening in bad time, it gives people somewhere to diversify into that is not fiat. If I wanted to take my money out of Bitcoin, I am not saying that is something I want to do. At the moment, I might have two choices. I could diversify into three choices. I could diversify into gold. Now I could diversify into some of the other blockchains out there that are doing interesting things. It is up to every person to evaluate what is interesting to them. Next question. Matt says, other than the scaling problem, what is the most challenging obstacle for Ethereum and Bitcoin moving forward? That is a great question. I have said repeatedly that, to me, the biggest problem is privacy. The reason privacy is a very big problem is that, if we don't have strong enough anonymity and privacy, the most obvious attack against these systems, when they get to a size where they start threatening the existing monetary control system, the big interests of banks, and things like that, is that, in countries where the rule of law is pretty weak, they are going to pass laws where they are going to punish you after the fact for things you do with digital currencies. Ex-post-facto laws, vague laws, laws that create enormous prosecutorial discretion, so they can make examples of some people, laws where you don't know if what you are doing is correct or not, but the penalties are extremely harsh, things like that, and all of those depend on the ability to find you and create consequences after you have done a transaction for that transaction. Privacy I think is really important, because privacy allows us to diffuse some of the legal attacks that are likely to come in the long-term and create a more robust network. I think that obstacle is more important than scaling. It needs to be solved in the base layer, because it can't be solved in the second layer.