Are there any examples of Proof of Value actually being used?


I have read around this a little, and it seems that Backfeed is the most frequently referred to initiative in this area. I have some observations that have lead to questions that are probably best answered by case examples:
Much of the model functions like a currency with partial pegging.
I am not sure how the governance of ‘dividends’ and minting works in practice, other than being an algorithm, if it is not then the politics of changes could be really ugly. If it is it could be pretty ugly.
The practical details of the assignment of value and reputation is not really clear to me. If one allocates reputation tokens, one needs to be in a position to evaluate contribution. This seems difficult.
So – rather than expose my ignorance further, I’d be delighted to be pointed at any formal presentation of how it works or any case studies.
Many thanks!