Thanks again, although just to note I can see just four replies numbered 2 to 5! :-)
I have been thinking about the vista you describe for some few years now (https://philipsheldrake.com/2014/04/organization-personal-reputation-first-principles-distributed-autonomy/) and keep getting stuck — fundamentally as it happens — at human behaviour.
It seems to me that you necessarily attribute all participants — developers, the people paying the developers, users of their software — with system-level understanding, from the hard systems (stubborn software code) to the soft (cultural ramifications). But I have found no evidence for such faith.
There is no cost of "loss of meaning", and so no barrier to hacking it together. and the effects of a 5-minute hack can endure for decades. And I think perhaps Facebook's success is all the evidence we might need to question any hope that individuals might leave a network once it's found demonstrably toxic.
Once loose, universal / non-contextual reputation will prove I think very difficult to undo. It's one of the reasons I'm a vocal critic of SSI / VCs.