It's great to have the data available like this - very effective.

Nice composite story - very clear and specific.

I really like the way the complexity of the conflicting evidence is documented her e- typical of vis design! Nicely communicated.

Can we point to any online examples in other domains (other than those above)? Actual instances from external sites?

This is really great. From my perspective the need to filter to single origins and destinations as flows become more complex seems important. Filter by magnitude too. Opacity shading when numbers of flows are big and crossings are high? Saliency bias remains and flow quantities are hard to show when they are skewed or vary by orders of magnitude. Colour may work better than width in these cases and thin lines don't allow colours to be differentiated well. Area-based OD map solution addresses both of these issues.

Very nice - there are a couple of typos and ToDos, but this is of a high standard and almost ready to go.