My project data is in NAD 1927 State Plane California 3 coordinate system. My site is approximately 2,700 feet wide. If I’m to publish this data to ArcGIS Online (AO), it is going to stretch to almost 3,400 feet wide, or by some 25%! This is a lot!!! I understand there are inherent, often unsolvable, differences between various projection systems; but in this case I can’t use AO – my clients just won’t understand (and believe) me. I still would like to take advantages of some new features in ArcGIS Online (except the, otherwise nice, background maps). For this to work, I wish I could change the AO’s coordinate system to match my own basemap. Until this is possible, AO is pretty useless for me (and probably other users too), since it’s unrealistic to expect the users to change their (often live fluid) data to the inflexible constrains of the only coordinate system (Web Mercator) available in the AO.