The implication of Figure 1 was that given the situation you find yourself in that you should choose to use the most effective communication strategy available to you. Figure 1 indicates that that the viability of communication options available to you varies depending on the situation that you find yourself in. For example, people on a co-located team can communicate in pretty much any manner they choose. Ideally they would choose face-to-face communication around a whiteboard or paper but there’s nothing stopping someone from writing a detailed document and then emailing it to someone sitting beside them. When a team is geographically distributed they have fewer communication strategies available to them, unless of course they invest in travel so that they can be face-to-face.
Figure 1 also indicates strategies for capturing, or persisting, a conversation. For example, a few people could have a conversation around a whiteboard, sketching the design of a screen perhaps. When they’re done, they might decide to take a digital snapshot of it so that they can retain the diagram to work on it later (many organizations still don’t provide permanent whiteboard space to their development teams). They may even choose to have someone write up notes, perhaps on a wiki or in a word processor, and embed the snapshot(s) into those notes.
To summarize, when it comes to how people communicate with one another they have choices. Disciplined agilists prefer to choose the most appropriate communication strategy for the situation that they find themselves in.