My earliest exposure to flow charts was as trouble-shooting aids. As I watched people use them, they did not seem very effective; users often got lost and the user experience rarely seemed to end with the trouble getting shot.
This last year, however, I have found myself going to flowcharting as an analysis tool, one to help me understand complex navigations or tasks where logical branching played an important part. For example, in one application, clicking the Done button could take different users to different locations depending on what path they had taken or decisions they had made.
More recently, I have been using flowcharts to understand how a complex task is done (configuring a network security appliance), especially to understand the different contingencies and how the user path is affected.
I use Visio's standard template for flowcharting and sit in design sessions with my laptop projected. The team of SMEs, information architect, technical writer, and I have been mapping the flow and logical branches of a very complicated process in order to create an interactive guide that could query the user about configuration decisions and deliver the appropriate information.
I have also created four new icons in my template, one for each of the main kinds of information:
An interesting pattern is emerging. Where there are decision/branching diamonds, there is often a need for conceptual and guidance information. In other words, the user needs some background about the domain and also needs expert insight into the decision to be made. For example, if a branch requires that the user decide between "transparent" or "routing" mode, the user assistance must make sure the user understands these terms (conceptual information) and also provide guidelines for when to choose one over the other, implications for that choice, etc (guidance information).
Procedural information icons tend to show up at action blocks in the flow.
Nothing shocking here, but it's nice to change lenses every now and again and find that the same features you thought were important still show up in the landscape.
So don't discount the value of flow-charting as a collaborative task-analysis tool, and be aware that it can then be easily turned into a contextual information requirements tool.