A little insight into drawing Web process diagrams

A buddy told me on MSN that the interaction designers in his company only produce flowcharts, and he asked me what criteria can be used to evaluate the quality of flowcharts. His statement completely shocked me - this is such a fine division of labor! I'm not sure whether it's good or bad. But upon further reflection, I indeed haven't carefully considered what makes a good or bad flowchart. This is a good opportunity for me to summarize my thoughts on this topic.