Can I use the Asana API to change a task from public to private or vice versa?
I've checked in the documentation (http://developer.asana.com/documentation/) and don't see anything there.
(I work at Asana)
We also monitor StackOverflow. :) You are correct, changing private/public visibility of tasks is not yet part of the API. Adding this functionality is part of the roadmap, but I can't comment on when it will happen.