Q59. Consider the following things1 that can flow or move on a network:

Used books
Money
Smiles
Gossip
Taught knowledge
Mooching friends/relatives
Email
Attitudes
Workers (flowing among jobs)
Infection
Packages
Greetings
Tips/how-to-info
Help/favors/acts of kindness

Categorize these in terms of four characteristics:

  1. The mechanics of diffusion: does diffusion occur via replication (copy mechanism) or transfer (move mechanism)?
  2. (applicable only to replication-based flows) Is the duplication is one at a time (serial), like giving a paperback to a friend, or simultaneous (parallel), like a radio broadcast.
  3. Does the traffic flow deliberately or blindly/randomly?
  4. Does the traffic revisit places it's already been? That is, is the flow on paths (no node repeats), trails (no edge repeats), or walks (visiting nodes and edges perhaps repeatedly).