What would a concrete example look like to you? They don't do these things on the internet or with apps, it's all face-to-face and word of mouth. I wouldn't bet on there being any academic studies of it either. Likely all we'll ever have is personal anecdotes from people who have been involved in these communities and somehow ended up spending much more time on the internet than is the norm there.
Someone else pointed out googling "tide as currency", and that opened my eyes. It made me realize that people doing this are working with pointers, not values.
