This is quite interesting.
It's a token on Ethereum which adjusts its own supply once per day, shrinking or expanding all account balances while maintaining their proportionality relative to each other, based on the price of the token as reported by oracles. The goal is to apply pressure against price moves away from the target price, which I think is $1. It's not a stablecoin, but will always be applying pressure toward the target.
So, for example, if at the time of the update the oracles are reporting a price of $2, the supply will be doubled.
It works by having two parts to a balance, one unique to each address and one universal. A persons balance is these two numbers multiplied. When a supply update happens, only the universal number is changed.
From what I gather from my brief research on it, the main purposes of the coin are to 1) create a digital asset that more closely resembles a commodity-money like gold. (As gold price rises, more people mine gold, increasing the supply), and 2) to create a digital asset that is more decoupled from Bitcoin (AMPL trading involves both price and supply charts, and will thus be more complex and look differently than other cryptocurrencies). This in turn makes it useful for things like being a collateral type in MakerDAO's MCD.
What I find coolest about it is the two-part balance feature that allows for super efficient supply adjustment. It's exciting knowing that there will be so many cool, weird, and/or useful token designs like that in the future.
What are your thoughts on AMPL?