This method may have a problem when dealing with more than one "Next Action" on a project. Where do you put the card when the next thing that you can do is "Call Bob re: project XYZ" and "Pick up two cases of doorstops from Lowe's for project XYZ". The idea of next action lists is to capture at least one action for each project, as well as any next actions that are not project related, and have them all available by context.

-Mark