The question of organization size is important for a geographically-dispersed organization with no hierachy, departments, or leader. A Blog Cooperative with thousands of members is likely to be unmanageable. Since discussions and decisions will be made through online interaction, Blog Coops have many of characteristics of online communities. In "Communities, Audiences, and Scale", Clay Shirky demonstrates that there are human barriers that prevent communities from growing beyond a certain size: "This barrier to the growth of a single community is caused by the collision of social limits with the math of large groups: As group size grows, the number of connections required between people in the group exceeds human capacity to make or keep track of them all." In Blog Cooperatives, members need be able to assess reputation and divide reponsibilities easily. So what should the limit be for membership? I don't know the answer to that, but my best guess is between 100-150.