Hi,

I'd say a community without structures is always smaller than the dunbar-number.

If you have a community that reaches that number it either starts being
fully occupied with itself, or starts falling apart into smaller groups
(possibly still of the same community, but then with rules and structures).

The networking between communities then depends on the environment the
communities exist in: size of meta-community (e.g. city), rate of change,
etc.

And on an individual level you'll have different types of people who may
be quite evenly distributed between the communities, like, one person
who is full member of 1 200-person communities, and that's all they
want / can handle, one person who is not really part of any community
but has 2 friends in 100 communities, but most fall probably into a
category of being member of two or three smaller communities (e.g. work,
private, and hobby), and then having friendly and/or professional
relations into other communities.

I'd say your proposition of communities between 150 and 150*150 members
with varying degrees of overlap, and no formal structures does not exist,
because you either have (in)formal structures, or the overlap will grow
naturally to 100% very quickly.


Sincerely,

Malte