Sorry I was never notified of your messages! I am getting your idea of the web of trust now. Totally on board explicit trust attestations and that zaps, likes, etc are useless because they can be gamed.
I'm on the fence re: hierarchies in practice as it seems useful but hard and rigid (even starting with baby steps). Had a look at tapestry and it looks interesting but definitely a rabbit hole in itself, I'll have to dive into it later. I fear making this even slightly complex will result in little traction.
My current idea revolves around simple trust attestations ("vouching for someone", I attest to the best of my current knowledge that this person has integrity - they're not a scammer or a psycho). Optionally with a few generic categories like (a) known them for years, (b) met them in person, (c) known them online, etc. I have ideas for UX around the creation of such events.
My current thinking is that hierarchy is an orthogonal concept, like if they know a lot about plumbing but nothing about cars or developing apps. Putting those two things together (hierarchy + trust) has to be probably done at the point of decision (which is how we do it IRL) and not be pre-calculated, and can be helped by (wot-filtered) reviews which are instantiations of both.