 Alexa asks, how important is it to be running a full node as a user of Bitcoin? It is important to you as a user of Bitcoin. If you want to know if a transaction has been confirmed, if you have received the payment, if you wanted to know if you have received, there are two ways to find out. One is to go to your browser and type in blockchain info, block trail, block cipher, one of these other blockchain explorers. What that tells you is that they think that transaction has been confirmed, and you only know that if no one has hacked them, there isn't a bug in their consensus algorithm. They haven't produced misleading information, they haven't decided to directly mislead you, and there's not a man in the middle or a compromised aspect of your own computer or browser that is displaying false information. Which means that you don't really know if a transaction has been confirmed. If you then turn around and use that information to make an expensive decision, like letting the other person drive off with your car, because a block explorer says that there has been three confirmations on the Bitcoin they paid you, you are delegating the responsibility and the trust model is broken. You should not be delegating that responsibility. You should use your own nodes that you've properly configured, that has been staying within consensus, and is properly upgraded to the level of the version of software that you feel comfortable with, that's running the types of capabilities that you feel comfortable with. You should ask that node, and that node will tell you an authoritative answer based on its own evaluation of the consensus rules. Now, can most users do that? No. Certainly the ones who are running companies need to. Certainly the ones who are running wallets with a lot of money need to do that. Most users won't, and that's why most users use a lightweight wallet, but they do so at a cost to themselves, and that's the cost of certainty. Now, that doesn't mean that it's also not an issue for the rest of the network. Not only is it good for you to run a node for your own reasons, but the more people running nodes and running them in a meaningful way, meaning they actually use wallet functionality, they actually use them to check if a transaction has been confirmed, they make economic decisions based on that node. If you're simply running a node on Amazon Web Services, where it costs $15 to spin up another node, that does nothing. It's on an infrastructure you don't control. It doesn't really do anything. You're paying for some of the bandwidth, okay, maybe it's going to help some of the other nodes bootstrap, but your control over that is very limited. So it's important to run a node, especially if you have the ability to run it on your own connection, on your own hardware, in the security of your own home or office. If you can run it with a satellite feed, wow, even better. If you can reconcile what's coming from the satellite and what's coming from the internet, even better, you can increase the resilience or robustness of this. Do it for principle, but again, not many can do that. Is it more important to have decentralization among miners, nodes, or both? Why? Ask Max. So it's important to have decentralization in every aspect of Bitcoin. Every point of centralization is a point of weakness and a point of potential failure, corruption, co-option, takeover, and banishment. When we say decentralization about miners, we have to think of it in three different and very distinct ways. Maybe even four different ways. First is the manufacture of mining hardware, specifically the high-end cutting-edge 16, 14, 12 nanometer silicon fabrication of ASICS. Centralization in that can drive centralization in the next stages. Ownership of mining hardware itself, the miners who own the mining farms, if you want to call them that. Really, what we mean when we say miners is the people who own mining equipment. If few organizations own the mining equipment and control how it is being used, that is a problem. Decentralization of mining geography, even if the mining equipment is owned by lots of people, if it is housed in few locations, both in terms of housing it in the same warehouse and housing it in the same vicinity, or geography, that is a problem. Right now, a very large percentage of the actual mining equipment, while controlled by many different miners, is located primarily in two provinces in China. Geographically, that is not good. Finally, mining pools, the interfaces for most miners to mine efficiently and spread out their gains, and smooth over the probability distribution of finding blocks and reward. We need decentralization in that. On miners, we need decentralization in manufacture, ownership, geography, and pools. We also need decentralization in nodes and types of nodes, nodes that are used by individuals to run wallets, nodes that are used by intermediaries to do merchant services, and things like that, nodes that are used by merchants as end-users to run e-commerce sites, and things like that, nodes that are used by wallet companies to run wallet infrastructure, nodes that are used by exchanges. All of those need to be decentralized. We need as many of those types run in as many geographies, connected with as many different media of connection, internet, dial-up, least-aligned, microwave, satellite, and whatever else we need to use, frequency-hopping, spread spectrum. So, decentralization everywhere is the key here. We need to have as much decentralization as many places. Of course, these things will ebb and flow over time. We will see some areas become more centralized, then they become more decentralized, then they become centralized again. It is not all moving in the same direction at the same time, which is the good thing. Changes in technology, in the operational models, in profitability, in the supply chain, will affect the centralization of all of those things. For example, in mining manufacture of ASICs, the biggest change that has happened is that we finally caught up to Moore's law and were right at the front-end of that, which slows down the incremental improvements in mining capability and performance, significantly, by orders of magnitude. That then changes the dynamics of the supply chain, because now you can actually ship that, and it will not be obsolete by the time it arrives somewhere that is 1,000 km away. You can put it on a container ship, move it for two months, and it is still a useful hardware platform after two months, which changes the decentralization of ownership and geography of mining equipment. Sometimes we will have external shocks to the system. If any country starts cracking down, and when Venezuela bans, mining, or requires everybody to get a license, it is a trap. Don't get a license. They are going to find you. When Venezuela does it, that doesn't have a big impact. If China was to do that, for example, that would dramatically change the economics and make centralization of mining a disadvantage. It would actually lead to decentralization of mining, if that happened. Lukas asks, is it possible to run a lightning node a few hours a day, like a full node? Can a lightning node shut down disrupts lightning transactions? Lukas, yes, it is possible to run a lightning node only partial time of the day. If you shut down your nodes, you will need, if you have outstanding channels that are open with prior states, you will need to essentially have a third-party monitor for channel closure to make sure that one of your payment channel correspondence doesn't try to cheat you by broadcasting a prior state. One of the very interesting innovations within the lightning protocol that happened after the original paper and was a great contribution, and I think it was mostly Tatch, Draisha, and Lalu who implemented this, was the ability to essentially give a third-party the monitoring role to monitor for cheating on your lightning payment channels. The only way you can cheat in lightning is by retransmitting a prior state that has now been revoked, that had a more preferential balance on your side of the channel, so pretending that you hadn't actually spent some of that money already in the channel by transmitting a prior state. The way you protect against that in lightning is that, if you try to do that, the other person who is being cheated has the opportunity and the keys to transmit a countervailing transaction, and while you're waiting to get paid for your cheat transaction for three days, they can immediately take the money, not just the money that you owe them, the money that you owe them, and the entire balance of the channel essentially a scorched earth policy where you are punished by losing everything if you try to cheat. But to do that, they have to be online to catch you cheating within that period of time that you're time-locked and waiting for confirmation. If you're running a lightning node part-time, you're going to need to transmit those revocation states to a third party that's running full-time, so that if they see someone trying to do that, they broadcast the punishment transaction, which immediately wipes the channel and saves you from being cheated and punishes the transgressor. The best part of it is the innovation that allowed, not only for you to do that with a third party, but to do it in such a way that the third party doesn't know what channels you have open or how much money you have in those channels. They only know if they see a cheat, they don't know until they see a cheat. So that's very cool. So you can run a lightning node part-time. It's part of the design, and that's what the ability to have a third party do the enforcement is designed for. Anonymous asks, how can a non-developers get involved with lightning? Well, if you have experience in user interface design, then you can definitely get involved in lightning. If you don't, then what you can do is download some of the existing lightning wallets and start using them, seeing where they work and don't work. Today you'd have to use them on test nets, but that's okay for testing. Help with the testing and give feedback to the developers. Ultimately, a lightning network wallet is simply a wallet. It should look like a bitcoin wallet. It should not be necessary for you to know whether the payment you just made was with Segwit, or without, with lightning, or without, on the base blockchain or on lightning, to a bitcoin address or a lightning public key. It should not matter. You should basically scan a QR code, say pay, and it will tell you how long that's going to take and what fees it's going to cost. You may notice that some of your transactions are much cheaper to execute and much faster to execute. Those are the lightning transactions. Some of your transactions are slower and a bit more expensive. Those are your Segwit transactions. Some are very expensive and slow. Those are your base bitcoin transactions on the most congested blockchain. That's the only indication you should get. Your wallet should not really tell you about how many channels you have open, who those channels are to, unless you go into some advanced setting. All of that should be invisible to the end user. It should be usable just like a bitcoin wallet is used today. Not all the lightning wallets are like that. Most of them are designed by engineers, and at the moment they're showing a lot of the background detail, and they're not very user-friendly. So check out Eclair, check out Zap, and have a look at some of these wallets as they come out, and help with the testing. Give feedback to the developers. I think that can be enormously helpful if you're a graphic designer or a user-based designer, even more so. Page asks, the white paper emphasizes the need for honest nodes to control the majority of CPU power. Is there a way for me as a non-technical person to help secure the network? Page? No, there isn't. At the moment, that aspect, which is the mining function, which requires you to have significant processing capabilities, is managed entirely by not CPU, but specialized ASIC chips, which are difficult to source. At the current level of competition, this is a viciously competitive game, which requires enormous investment. You can dip a toe into this pool if you have, say, $50 million to spare. You'd probably need to hire some very, very technical people to actually pull that off, otherwise you can kiss your $50 million goodbye. The average person, the non-technical person, cannot help secure the network through that function of controlling CPU, but they can help secure the network. By running a node at home, using it to validate transactions and to see if they've been paid, for example, maybe connecting a satellite dish, certainly running a node, choosing which software they run, and also choosing very carefully what types of wallets they use, what types of exchanges they use, and use ones that align with their own principles. That's very powerful. You can get a lot done just through your choices as a consumer and by running a node at home. It's also a good learning experience.