Start with a sentence what we mean by this and why it is important.
Commons work best at smaller scales because human conviviality requires personal and social connection. Evolutionary scientists often point to the so-called "Dunbar Number" -- named after anthropologist Robin Dunbar (wiki 
) -- which postulates that, given the size of the brain neocortex, humans can maintain stable relationships only with about 150 people. Apart from such apparent physiological limits on group size, distributed structures for commons helps ensure that power is not consolidated and abused, and that governance is responsive to local circumstances.
discuss if "commons work best" at a smaller scale: I am not sure, actually one could put it the other way round and say: wikipedia works better than any small commons (I am exagerating); I'd say that the argument goes like this: That Commons work at a smaller scale, now and in the past, has been proven around the globe in countless case studies (point DLC or the fieldwork by historians): But they require personal and social connection. The interesting question is; does a commons framework/approach/ practice apply beyond small or medium sized groups. ... and so on
The general history of the commons, then, has been one of distributed, autonomous structures of relatively small-scale groups. Historically, hundreds of thousands of discrete natural resource commons -- based on farmland, forests, fisheries, pastures, water, wild game, etc. -- have been autonomously managed, with little or no state involvement.
In modern times, many institutional infrastructures and tools -- law, bureaucracy, hierarchy, the Internet -- have been invented to help enlarge the size of stable, functional groups. While this has enabled the creation of large, modern institutions, it has also facilitated the centralization of power and control at the expense of individual participants and local knowledge.
The challenge of contemporary commoners, then, is to find ways to adapt modern institutional forms so that they can support human empowerment and conviviality, not simply the consolidation of power. Distributed commons are an attractive way to do this.
"Scaling the commons" can be achieved through a process of emulate & then federate, especially via the use of digital networks. In this fashion, the advantages of distributed structures AND larger-scale cooperation can be combined.
POST http://image-transporter.apps.allmende.io/image
# Alternative numbers Anthropologist H. Russell Bernard and Peter Killworth and associates have done a variety of field studies in the United States that came up with an estimated mean number of ties, 290, which is roughly double Dunbar's estimate. The Bernard–Killworth median of 231 is lower, due to upward straggle in the distribution, but still appreciably larger than Dunbar's estimate. The Bernard–Killworth estimate of the maximum likelihood of the size of a person's social network is based on a number of field studies using different methods in various populations. It is not an average of study averages but a repeated finding.[15][16][17] Nevertheless, the Bernard–Killworth number has not been popularized as widely as Dunbar's.
may be we should rely on this one ...