The #MarchOffTwitter h/t first appeared on Twitter in this tweet: https://twitter.com/LNcyberhub/status/1628405979820834817
Since then, dozens of other bitcoiners have also tweeted it as well. The idea is that bitcoiners are leaving Twitter and migrating to Nostr instead, myself included: https://twitter.com/1GLENCo/status/1630835005021724673