In 2017 Bitcoin nearly tore in half. One camp wanted Segregated Witness, a change that raised capacity without enlarging blocks. Another wanted bigger blocks outright. The argument ran for years through mailing lists, conferences and increasingly ugly social media — but it was also fought in the one place neither side could edit afterwards: the coinbase field of the blocks themselves.

Miners have always used that field to sign their work. In 2017 they used it to declare allegiance. Two slogans dominate the record.

BIP148 marked the user-activated soft fork — the plan to force SegWit through on 1 August 2017 whether the large miners agreed or not. It appears in our archive from 2 April 2017, and it is conspicuously the smaller operators: Slush Pool, the oldest pool in Bitcoin, and Bitcoin-India, whose miners at one point replaced the usual big-block signalling parameters with a pile of excrement and a screaming face.

NYA marked the New York Agreement, struck in May 2017 among exchanges and the large mining pools: SegWit first, then a doubling of the block size some months later. It appears from 17 June 2017 and it is overwhelming — more than 18,000 blocks carry it. For most of that summer and autumn, a majority of the world's hashpower was signing its blocks with a promise.

Note who signalled first on each side. Bitfury tagged /Bitfury/SEGWIT/BIP148/ in April, then /Bitfury/SEGWIT/NYA/ in June. The same pool, both banners, ten weeks apart.

The irony is in the pivotal blocks. Every one of them was mined by a pool flying the NYA flag. The last block before Bitcoin Cash split away came from BTC.COM/NYA/. SegWit locked in at block 479,707, mined by BitClub Network/NYA/. And SegWit activated at block 481,824 — mined by BTCC, whose coinbase read /BTCC/ Support /NYA/. The upgrade its opponents had spent a year resisting was delivered, in the end, by blocks carrying their opponents' slogan.

The second half of the agreement — the block size increase — was called off on 8 November 2017. You can watch the movement die in the tags. NYA appears in 3,911 blocks in September and 3,814 in October. Then 1,370 in November, 285 in December, and a thinning trickle through 2018 as pools forgot to update their templates. Nobody announced it. The signal simply stopped.