Ask HN: How would I send 1 dollar to everyone on Earth?

Now that's the kind of inequality I can live with.

There might be some distopian way of doing this using biometrics and cryptocurrency. Submit your "human hash" (e.g. some set of cheaply collectable and individually unique biometric signatures) and receive one USDT or similar fixed value digital currency. Then just slowly allow people to register ownership of their dollar as/when they decide to collect it. This only gets to people who can get access to a computer and the crypto-dollar is functionally useless to most of them but it's pretty cheap to distribute. The biometrics bit may also be literally impossible - no idea what the state of the art there is like.

Another potential problem is people being born or dying after you’re collecting your data and running your job.

#3, that’s a good one. I started a long-running job like this and it failed in the middle after sending money to N people, and Airflow or L1 support just mashed restart. Now the first N people who got a dollar before the job failed each get 2 dollars (or 3 if mash retry again). Now you ran out of money, or you treated the last M people unfairly. (That’s how I learned “idempotent”.)

One solution is to keep a log of the people you sent the money to and do a left outer join with the people_to_send_dollar_to table when the job starts. Then you filter out anybody in the people_we_already_sent_dollar_to table in your query so your job never iterates over them again.

But now it’s worth thinking about if you succeeded sending somebody the dollar but they failed receiving it (it got stolen out of their mailbox or it fell out of the delivery truck). Do we need people to tell us when they received the dollar and resend it periodically until we get the confirmation message? What if we never get the confirmation message? Is this the 2 generals problem? What if some people never confirm so they can keep getting dollars in the mail?

Is the answer cryptocurrency?

Global distribution is complex. So there is no easy way to do it. Now, what is the option here? Your assumption, around 6 billion of those humans have a bank account. So, we can leverage the bank network to do the distribution.

There is a chance of the same person opening multiple account. Integrating with one bank at a time will help not to do manual transfer and build a centralized database for verification simultaneously. There is no time limit here, I assume this is fine.

How about the rest, the unbankable? Via country social aid. There is a high correlation that the unbankable is similar to under poverty population. With social aid, it will reach them. Cross-check with the central database for verification.

Now, what if the 1 dollar doesn't need in the form of physical money? There are so many alternatives to this. I said, follow on how people spend money.

You can use it to pay each Taxpayer all countries, pay the debt of each person in the bank, and subsidize commodities that the unbankable population consume: data, rice, bread, electricity, vaccine and others thing that people spend. So, understand how unbankable people spend and receive money.

There is a cost of distribution. My rough intuition is probably around 30-40%, if we are looking for precise in-person equal distribution. Yes, that is really expensive, even more for unbankable, because most of them will receive cash.

Thank you for the question @paulluuk. This is a good brain exercise and seems like consulting interview question for me hahaha

The same is true of a dollar. If I gave a new born baby a dollar and a person on their deathbed a dollar, the baby will gain much more of a benefit.