In the recent thread on sybil attacks, this question got me thinking a bit :
(In english : what is the point of having an arbitrary large community if you can just exchange your currencies between communities)
And I think I found an issue with the way we imagined how the communities should work in practice at the last FMM5. In a way this problem is already present with today’s currencies, however I think it is important and makes uCoin currencies somewhat “non-free” in the Relative Money Theory sense.
So we argued that in order to discourage Sybil attacks and keep the communities at “human size”, we should impose a strict limit on how big an economic community can get (fixed at the creation of the currency). And that, as it’s only electronic money based on the same protocol, it would be very easy anyway to exchange between different currencies if you need to travel temporarily in other communities.
So imagine uCoin currencies start taking off a bit everywhere, and become the main medium of exchange in at least a decent amount if different geographical places (from what I got the communities would be of the size of a relatively large city).
To me this only amounts to creating one big uCoin meta-currency, with the UD from each currency being a sort of “coin” in this meta-currency but which may have different values (we can take any single currency as the reference point and the given rates of exchange to specify value in this meta-currency).
But then a person receiving a UD in a very popular place, say Paris, that a lot of external people come to visit, will have a huge advantage over a person coming from an isolated community (let say a conglomerate of tiny villages in a warzone). The exchange rates would be much in favor of people receiving a Parisian UD than a warzone UD.
As I said it is a phenomenon that is already present with the currencies in use today, however I think having a large amount of relatively small communities will exacerbate this problem. Effectively offering very high mobility to people coming from popular communities and further isolate people that come from already isolated places.
So even if you have a “free” monetary system within a given economic area, it does not mean that you can have a “free” relation between different communities. That the union of several free communities doesn’t create a larger still free community seems like a problem to me.
In our world where traveling is becoming always easier and more frequent, I think this is something worth thinking about. I haven’t read all of the RMT book and maybe this is already talked about in there, but from what I got it makes the assumption of “pseudo-isolated” communities, and I’m wondering if this assumption will be useful in practice, and in particular with regards to the size limit we want to put on uCoin communities.