Mentions of https://voxpelli.com/2011/10/activity-streams-flattr-api/
Thanks for writing this!
This has my full support and what brought me joy while building ActivityStreams and IndieWeb solutions through the decades (voxpelli.com/2016/03/my-2..., voxpelli.com/2011/10/acti... etc)
I would gladly add myself as a signatory if you want.