Brains Pool, also formerly known as Slush Pool and Bitcoin.cz Mining, is the oldest mining pool, and the first known to be publicly available. Slush Pool was announced on November, 27, 2010 under the name Bitcoin Pooled Mining Server and operated on a share strategy that involved an artificially low difficulty method that has since been determined to be vulnerable to cheating. The pool now follows a score-based method, where older shares (from beginning of the round) have a lower value than newer shares, which serves to demotivate a cheater from switching between pools inside a round. Balances accumulate on the server, and are sent out when a user-set threshold balance is reached. There is a fixed fee of 2%, as of December 10, 2017.
In September 2022 Slush Pool has been renamed to Brains Pool.