Placement of App Inventor in high school CS curriculum Over the past couple days I've had my first opportunity to dive into App Inventor. It has quite frankly blown my mind. I had always (mistakenly) grouped it with Scratch, Snap!, etc. as "just another drag-and-drop environment." It is that but so much more (I can finally see that now). 

Now I am wondering where it best fits into a typical high school sequence of CS courses. I could see it being anything from a semester-long intro elective for students with no background to an advanced app development class for students who have completed AP CS A (and thus are quite competent with OOP and Java). 

Where does a class focused on App Inventor fit into the high school CS curriculum, and what are the merits of it having said placement?
The AP course that @AlfredThompson referred to is the Mobile CSP course. It's a
complete College Board-endorsed course for the new AP CS Principles course and is entirely based on App Inventor.  It comes with a complete set of lessons for students (Creative Commons-licensed) as well as lesson plans and professional development (PD) resources for teachers.  The MobileCSP project has been providing PD for high school teachers throughout the U.S. since 2013 and has now trained around 500 teachers. For more information about the project, see this site.