In ArcMap, ESRI has ZoomIn with backward motion of mouse wheel and ZoomOut with forward motion, opposite to what's in Google Earth. Now, ESRI is following the Google Earth path in ArcGIS Online maps.
ESRI should be consistent at least within it's own domain and be consistent in all of its applications. If ESRI is going to follow Google Earth in ArcGIS Online, it should change to the same pattern in ArcMap.