Blockchain

Kraken exchange (the one I'm using) looks like they disperse the money across a lot of different accounts. They do multi-account transactions. I looked up a deposit I made into an account with a public key they made for me and followed the transactions on the blockchain, and my deposit was grouped up with money from 10 other accounts (one of which was a 20BTC deposit... oof) and then sent collectively to 15 different accounts. I did hear that multi-account stuff was possible.

So you basically say "the combined value across these 10 accounts of x,y,z each is going to be sent to be divided this way across these 15" - so you don't really have a concept of one account sending to another, but it's pooled and re-divided according to what the input is.

So say you and I have bitcoin and live together and want to pay our electricity, gas bills, and rent all at the same time. We'd have an input of 2 BTC each (let's say), and then the transaction has 3 BTC going to rent, and 0.7 going to electricity, and 0.3 going to gas. And that's all bundled up as a single transaction to save on transaction fees. Multi-account transactions do cost more in fees, but it doesn't scale linearly so I guess it's more profitable to bundle them up when you can.

The coolest things I've seen though are smart contracts. I assumed it was some weird wank that was impractical or stupid for the sake of adding "blockchain" to things

And to be clear... a lot of them are

But I saw some examples of how it could work in Ether where you can build pre-made payment triggers into things to allow people to trade without trust

Or to add micro-transactions to an application without depending on any central server to mediate the transactions

So let's say you want to buy a car - the details of the car and its ownership title can be put on the blockchain just like a coin itself. You list the sale of the car as a piece of code that triggers when the first person sends the amount required to the nominated address of the sender. When the first person sends the money, the sender's public key becomes the new owner of the title deed. If someone else tried to buy the car at the same time, the blockchain would auto-reverse any incoming transactions because it would no longer match against the encryption of the new owner since they hvaen't re-listed the car. If title deeds in blockchain are recognised legally (which some ownerships currently are since it's proven to be tamperproof), then you can skip out on a lot of lawyer fees where you need to confirm it's not stolen or being sold without consent etc.

Now for something more advanced, let's say you create a YouTube-like service - this is where it gets weird. I hear about this idea and thought "making a blockchain YouTube competitor is the stupidest thing I've ever heard of"... but... someone creates some code for a video service where anyone can upload a video file to the blockchain with publicly-indexed information like a title and tags and description etc. Then the video has some kind of price for viewing optionally attached with the video creator's wallet's public key attached. Then when anyone wants to view that video it's encrypted to start, and the smart contract is that you send some small amount of money (like 2c let's say) in exchange for a key to be able to download the file and watch it. Bitcoin miners currently use their bandwidth and CPU/GPU power to get tranaction fee shares, and with a video service it would be similar - someone hosts the video and streams it to you with their internet connection encrypted to you. You've got the key because you paid the fee for it, and then you can watch the video. Obviously you'd need front-end apps to mediate all this so it's seamless but none of that is unknown territory - between BitTorrent and Tor it's quite proven tech to stream encrypted data over a decentralised network. So that 2c you pay to watch that video might be split so that the person hosting and streaming it to you gets 20% and the creator gets 80% - who knows. Maybe the creator put it up for free so it's only 0.4c to watch it.

And now you have a DAO - decentralised autonomous organisation - a company that runs a video streaming service like YouTube but there's no company behind it. The company is the code that mediates people in a network to do what YouTube was taking a 50% cut for. YouTube makes billions of dollars and cuts out creators who make controversial content. With something like this, creators would get paid for each view, there would be no ads, and anyone could join the network by using spare internet/HDD space to host streaming nodes. Anyone can upload content and get paid for it, and it's all guaranteed without people having to form partnerships and trust each other not to take the money and run or demonetise people after they've made or hosted content

And because it's completely decentralised and encrypted, in theory it would be impossible to censor anything - for better or worse