When trying to understand the general trends in a network, or exploring the differences between networks, staring at hairballs is not particularly useful (as much as my cat tries to convince me otherwise). Quantitative measures of large-scale network structures make it possible to characterize and compare different networks.
Large-scale structures can help you approach questions including the following:
- Is a network becoming more or less resilient to failures as it grows?
- How far does data or electricity need to travel as it moves across a network?
- How centralized is a network?
- Do nodes cluster into tightly connected groups?