A blockchain is a trustworthy computing platform. That is much more important than it sounds. It's not just "we made this system 17% more secure"; it's a whole bunch of new abilities that we haven't really had before.

Here are a bunch of ways of looking at it:

• Transparent workings: Stuff that can be trusted to work the way it says it works

• Less need for large orgs Stuff that can be trusted even if there's no large organization backing it

• Censorship resistance: Stuff that can be trusted to work the way it says it works, and nobody, not even the company that created it, or the government, can stop it

• Ledger of record: A historical record that can't be altered

• Collaborative construction: Social media systems that are about building (and getting paid), not just socializing

• User-owned networks: Networks where the users can own a share of the network that they are helping to build

• Hard money: Money that isn't vulnerable to devaluation (inflation) by the government/central-bank

• AAA something about composability?

The code of an on-chain application is completely visible. That is, anyone can ask the blockchain, "Show me the code for this app," and trust that the blockchain will show you the code honestly and that the app will execute as-programmed.

How many of the problems in the world today could be described as, "This org said they'd do X, but we don't trust them to actually do it"?

In the old world, organizations claim that they'll do X, and then we just kinda have to trust them to do it. In the new world, organizations write code that they claim will do X, and then anyone - including you, but more realistically various computer nerds ("auditors") who are unaffiliated with the people who wrote the code - can just look at the code and verify that it really does do X.

Blockchains let us make things that can be trusted to do what they say they'll do even if there's no big company with a brand name backing them.

Or to put it another way: blockchains reduce the need for large organizations.

One of the reasons we have so many large orgs in the world these days is because they really are more trustworthy, in some ways, than individuals or small teams, because they have a valuable reputation to protect. People grumble about banks and Big Tech companies and so on, but if some random guy said, "I'll be your bank, store your money with me," you'd laugh at him.

With blockchains, individuals or small teams can create things that are just as trustworthy as things created by large organizations.

When we say that on-chain code can be trusted to do what it says it's going to do, part of what we mean is: and nobody can stop it.

I don't mean to sound too nutty about that. Obviously there are still lots of things that governments can do. If the government isn't happy about a particular app and the creators of that app are developing it under their real names, then the government can put pressure on them that way. Also, a government might attempt to crack down on usage of the blockchain as a whole - I doubt Western government will be capable of this, but IIUC the Chinese government is having some success with it.

And as for the company that wrote the code: of course the authors could write in a backdoor, and that's a common thing for blockchain developers to do in the early days of an app, before it's fully established and solid, so that they can update the code to fix bugs and stuff. But that backdoor will be visible in the code for anyone to see. And in the long run, it's common for the team to "progressively decentralize" - gradually relinquish control of the app, either making it fully autonomous or transferring control to a DAO or something.

A blockchain is a trustworthy history of all the events that ever happened on it. That's part of why it's so useful for implementing new currencies and other financial infrastructure: e.g. Bitcoin keeps track of all the "Alice sent 0.3 BTC to Bob" events.

AAA this one feels less compelling at the moment; you kinda have to be a conspiracy nut to not trust the legacy world's histories.

Now we're starting to get into some of the uses of blockchains that are specifically about money.

Web 2.0 has been extremely successful at making it easy for anyone to make payments, but hasn't done nearly as good a job of making it easy for anyone to receive payments.

In Web 3.0 (a term that kinda just means "the Web, but with blockchains"), it'll be super-easy for anyone to receive money. Which opens up all sorts of possibilities for new kinds of "decentralized autonomous organizations" (DAOs) and social networks that let people do work and get paid for it. Web 2.0 social media is largely about chatting and socializing and tweeting and posting; maybe Web 3.0 can be about building.

It is super-common in the crypto world for projects to have a "token" that confers a share of ownership of the project (either a share of the project's profits, or a vote in the project's decision-making, or both). (e.g. Staked ETH, COMP token, ENS token, etc.)

My understanding is that this kind of thing is illegal in many places in the real world, due to regulations on investing. (e.g. Facebook isn't allowed to offer its users shares of Facebook-the-company in exchange for using Facebook-the-app.) But it seems like a very important and useful mechanism to have in our toolbox. For systems that have a network effect, it often makes a lot of sense to treat the users (particularly the early users) as valuable participants who are helping to build the network effect and so there should be a way to compensate/incentivize them with (or for them to explicitly purchase) a personal stake in the overall network.

This is more important than it sounds. A huge number of humanity's problems could be described as coordination problems of the form, "We're all doing X, we all understand that doing Y would be better, but nobody wants to be the first to switch from X to Y, and we have no way to coordinate a jump en-masse from all-doing-X to all-doing-Y." Tokens give us a way to do that kind of en-masse-jump: because token upside is inversely proportional to network effect, they can incentivize people to want to be among the first to do Y.