Google Analytics: How to display traffic data of all my sites as one graf?

Question

As a webmaster I support N different client sites. How to display all their traffic data at one joint graph conveniently?

Answer 1

If "n" is something in the hundreds or thousands you can use the recently announced APIs for Large Companies.

If your needs are somewhat smaller you can pull the data into a Google spreadsheet (via Google apps script) and use the Chart functions (or Google Charts) to create a combined graph.