50BTC.

50BTC was a Bitcoin mining poolMining poolA group of miners who share the work of finding blocks and split the rewards, so each gets paid steadily instead of rarely. at 50btc.com, set up in 2011, which never said who ran it. Its site was in Russian, English and German, and it paid miners in bitcoin or through Russian payment services such as QIWI, Yandex.Money and WebMoney. It paid by pay per share, or PPS: a set amount for each piece of work a miner sent, whether or not the pool found a block. So each 50BTC block’s first transaction paid the whole reward to one pool address, and the pool paid its miners separately. These are payments to the pool’s miners, separate from the transactions confirmed inside the block.

50BTC said it became the world’s largest pool on 6 October 2012. mempool.space credits it with blocks only from 6 February 2013, when they began to carry its name; that year it found 6,346, one Bitcoin block in ten, and in some summer weeks more than one in five. From August to October 2013, 50BTC said, cheating miners, floods of traffic meant to knock it offline and a hack of its billing system cost it its record of users’ balances and “a huge part of the funds”, and it stopped paying out. It came back in January 2014, tagging its blocks “50BTC.COM resurrection”, but found only 60 more, the last, 303,841, on 2 June 2014. That month miners on the BitcointalkBitcointalkThe Bitcoin forum Satoshi Nakamoto opened in November 2009. Much of Bitcoin’s early history, from the pizza offer to Satoshi’s last post, happened there. forum wrote that it had stopped answering them and paying them, and on 17 June a moderator, Con Kolivas, closed its thread there, writing that the operator had been given “plenty of opportunity to respond”. No closure announcement has been found.

mempool.space also lists one block from 11 January 2024, 825,246, under 50BTC. That block was mined through ViaBTC: its first transaction pays ViaBTC’s address, and its tag reads “/ViaBTC/Mined by 250btckz2/”. The letters “50btc” in that miner’s name match the tag mempool.space looks for in 50BTC’s blocks.