I saw this nostr note by @fiatjaf:

and it made me curious about whatever this inkan thing was. It claims to be:

I was digging in to it a little, but it seems that fiatjaf was faster than I and if you follow the thread the inkan scheme gets progressively more and more complicated, eventually involving timestamping nostr notes onto bitcoin via opentimestamps and using ethereum smart contracts. Oh dear.

I need to get better at spotting these things from the beginning before I waste half an hour trying to figure them out.