looks like the first GM on Twitter was “GM! Merry Christmas!!!!” on 12/25/2006

and most of the replies are from web3bros in 2021/2022, smdh https://image.nostr.build/ff4b007e2886a37455c2759180104089fbfab2e760c675a22855730d9ca7bbfd.jpg  nostr:note1axcq6sy2p4xsjj7kghmakxfzd32pmt656nvt0y3eqx6zf6u5u49sqktrxj