 What are the most exciting or useful features that are being worked on for the Lightning Network? There seem to be a lot of different upgrades to the Lightning Network being proposed, such as, for example, watch towers. Which of them do you consider to be the most exciting or most useful? Well, David, thank you, great question. So watch towers, as an example, is one of the things that we've seen being introduced into the Lightning Network. And watch towers are basically a third-party service that you can subscribe to that protects your channels when you're offline. You remember when I was describing the Lightning Network earlier, I said that in the first iteration of the Lightning Network, due to the way in which the channels are constructed, it is possible to broadcast the prior state, which means a different mix of local versus remote balance that would disadvantage one of the parties in the channel. Basically what that means is, I sent some money to Rene, for example, over our common payment channel, and I want that to have never happened. The state of the channel before I sent that money shows more balance on my side, which is advantageous to me. That state should be invalidated when I send the new state to Rene, but I can cheat by sending the old state in the normal protocol. If I do that, Rene has a period of time in which Rene can punish me by sending a penalty transaction out that not only gets the state back to the correct state, but actually takes away my balance to punish me, which means that I lose all of the money in the channel if I try to cheat by keeping more of the balance. Now, that penalty transaction has to be broadcast within a period of time, and if Rene is offline, I can cheat while Rene is offline, and as a result, keep a bigger percentage of the balance and close the channel. To prevent that, Rene either has to be online all the time or with watchtowers, Rene can outsource that. Rene can say, watch this channel, and if someone tries to broadcast a prior state, please punish them on my behalf by broadcasting this penalty transaction, and watchtowers can charge a fee for that, and there are services that are operated according to a new standard that is implemented in the number of the clients on the Lightning network. So that's one development. A couple of others. Crampoline routing is an interesting one. So this is where instead of my client, my Lightning wallet, needing to know how to construct a route that connects the payment channels that I have and then further payment channels to get to a recipient somewhere out there on the Lightning network. Instead, I outsource that function to an intermediary node called the trampoline node, and it's called the trampoline node because essentially what you do is you bounce the payment off that trampoline node, and the trampoline node does the routing from there. So all you need to know is know how to route to that trampoline node. It doesn't have to be a node that you have a payment channel to. It could be several hops down, but you only need to know the route to that trampoline node, and then the trampoline node finds the route to your recipient. This is a great service because that means you can now run a lightweight Lightning wallet, let's say on mobile device, that doesn't keep a full map of the channels that are available on the entire Lightning network in order to construct routes. Instead, it relies on the trampoline node to keep a full map and therefore find routes, and that makes things a lot easier. But of course, there are some downsides to that because the trampoline node gets a construct route. It has the ability to deny service to you or sensor, unless you use another Lightning trampoline node, and it also leads to a small reduction in privacy because the trampoline node knows the ultimate destination. Another mechanism for routing is rendezvous routing, where the recipient of a Lightning payment tells you to route the payment to a specific node that isn't that node, effectively a node further away, and then uses either private channels that are not advertised or another route that communicates the rendezvous node to route it for the final few hops. Now, think about it for a bit. The advantage of that is that you can increase the privacy by hiding behind an intermediary node and using private unpublished channels to route the last few hops. And you can combine the techniques we just talked about. So you could use trampoline and rendezvous theoretically to have the trampoline node route to a rendezvous node from where the routing is hidden to the final destination. Take back some of your privacy. Hoddle invoices are another very interesting innovation. Hoddle invoices are invoices that do not expire and where the payment doesn't have to be claimed immediately. Instead, the payment is established but then held for a while and the recipient nodes can leave it. You can do a number of interesting tricks if you have that kind of delayed payment with Hoddle invoices. Another interesting one is turbo channels or using push to push balance when you open a channel in the first place. So this is a way to send money to a node that you without receiving an invoice. And it's also a way to establish inbound liquidity for your own lightning node for fee. So in this case, what you do is let's say I wanted to send money to Carol and Carol has not given me an invoice. I can open a channel to Carol and push an amount so that when the channel is initialized, some of the money is actually on her end of the channel as her balance from the very beginning and effectively I paid her that money by establishing that channel. And you can also do that with a service provider that can open a channel to you to create inbound liquidity and also push some of that as a payment to you. You can use a number of other tricks like that. Another interesting development is development of submarine swaps or submarine payments. And this is where you do an on-chain transaction to a Bitcoin address that also funds a lightning channel. So pay this Bitcoin address so I can open a channel or the opposite, pay this lightning payments so I can make an on-chain Bitcoin transactions. So this is effectively an atomic swap between on-chain and off-chain payments so that they can occur atomically and trustlessly. And so you can move money essentially from on-chain to off-chain or from off-chain to on-chain. These are just some of the developments and these are just other things that have emerged to fulfill specific needs and reduce complexity in the use of the Lightning Network just over the last year and a half in its development. And these developments are coming very, very fast from all corners of the developer ecosystem in Lightning. If you enjoyed this video, please subscribe, like and share. All my work is shared for free. So if you wanna support it, join me on Patreon.