This week Jason Cassidy and Davey Slimmon discuss the concept of the ‘aboutness’ of content and the challenges of determining it. They explore the use of AI and NLP in indexing and abstracting content, as well as the desire for natural language processing in querying computers. They also discuss the potential role of controlled vocabularies in bridging the gap between human understanding and machine interpretation, and the importance of considering the effort required to pre-calculate and organize data in finding information.