I've used the iceberg as a metaphor for group dynamics or group processes in teams versus content. The content and what's being said is the tip of the iceberg and the groups dynamics are all under water. Anecdote has published a white paper called: Our take on 'how to talk about Knowledge Management'.
They use the same metaphor of the iceberg to explain the difference between data, information and knowledge and it works very well too. The tip of the iceberg represents data and information. It is the domain of data and information management. It requires a certain skill set. The bulk of the iceberg below the waterline represents the knowledge in people's heads. The water the iceberg is floating in represents the organisational culture. In this domain below the waterline, a completely different language is used.
A great metaphor because it explains how professionals working above and below the waterline may clash and may find it hard to collaborate. However, if you understand the complementarity, it may help. It may look like advocating the underwater knowledge management, but both approaches are equally valuable and necessary. When a knowledge management initiatives focuses too much on data and information management, it may not have the expected effect on the (invisible) knowledge creation and innovation side.