I thought Peter Selinger was on here, but I can't find him. Has he left us?
Just looking at this interesting new paper https://arxiv.org/abs/2604.20964 which does cite Mathstodon posts by Pieter Mostert (npub1l3c…nw2k).
(Christian Lawson-Perfect (npub197g…q2n4) first citation of Mathstodon in a paper, or have there been others?)