I'm trying to sort out the relationships among accounts, subscriptions, and organizations in My Esri, ArcGIS Online, and ArcGIS for Developers. I haven't seen a comprehensive and succinct document from Esri, so hopefully someone here can help me out. Here's what I've got:

An Esri Global Account is associated with one email address. An Esri Global Account may be associated with a My Esri Organization. An Esri Global Account may be associated with one ArcGIS Online Organization. A My Esri Organization and an ArcGIS Online Organization are different, unrelated things.
Not sure how ArcGIS Developer subscriptions fit in.
Can anyone add to this?