Neo4j is a graph database (nodes and relationships) and is the perfect fit for some types of problem. Within that domain Neo4j is much, much faster than SQL and easier to query. Py2neo is a Python binding to Neo4j. The live presentation showed how to create word transformation puzzles e.g. getting from "stores" to "slaked" by one latter transformations where each intermediate step is a valid word. One solution is "stores"->"stored"->"stared"->"staked"->"slaked".