There are diverse optimal size networks, it depends what kind
of application you have.
In our case: "Networks Laboratory in Social Systems Apply Mathematics at
IIMAS-UNAM", we are studying several networks as follows:
1. Political Netwoks: size = 6,000 nodes, some subnetworks have a size =
others around 500 nodes. In this case networks with 500-1000 nodes have the
2. Academic Networks: we are studying the academic network of The National
of Mexico from 1910 to today. The network from 1970 to 1990 is about 450
those who have received a prize, like National Academy of Sciences of
Mexico, National University
of Mexico Prize, Prince of Asturias Prize, etc), and there are secondary
nodes, more than 3,000
people to whom there are connected.
If you need some more details tell me please.