Definitely, reach and depth are two different dimensions but I am not sure if increasing one need to lead to decreasing the other. That would be the case only if social capital were a fixed 'asset' which if shared further, grew thinner. As an economist, I think of social capital as well as an asset and, as it name indicates, a capital. So, it can accumulate (with more or less returns over time) and also deteriorate or depreciate. It can depreciate becuase of a broader use or becuase of an improper use. What I truly agree with is that there are some specific pockets of deep trust. I am not so concerned with size being the or a critical factor but with deep trust is only a product of exclusion of others.