What TAO is, and what a subnet is

This lesson slows down on two words everyone else assumes you already know: the currency, and the place it's earned.

TAO is Bittensor's own currency — the thing the network actually mints and hands out to reward useful work, rather than anything printed by a company or a government. [source]

A subnet is best described as an independent contest: it has its own participants and decides, entirely by its own rules, who is doing good work in one specific field. [source]

There can be up to 128 of these running at any one time, each identified only by a number; when that ceiling is reached, launching a new one means retiring whichever existing contest is earning the least. [source]

Each contest also runs its own currency: a token called alpha, traded against TAO inside that one contest's own small market. Committing money to a contest is what buys it at the going rate; pulling that money back out sells it again — and what you hold in one contest is worthless in another, they don't mix. [source]