Suppose you are the family genealogist. As it takes time to fully research and flesh out the family tree, the tree grows and evolves over time and you would like a way to let the extended family know what the tree looks like from time to time.
Enter NetMailBot. Not only could you send mass notice emails to everyone in the family about the current state of the family tree, but you could send customized emails requesting various kinds of genealogical information. If you had the genealogy stored in a database, you might be able to automatically find all relatives whose siblings are unknown, or who were known to have had children but some details remain sketchy.
Using NetMailBot, you could comb the database for missing information and automatically send that email to Aunt Flo asking her exactly how many brothers and sisters her great uncle on her father's side had and what their names were.