It appears that setting a default map allows me to have the website remember that I prefer the "ArcGIS Satellite with Labels" background. How does that default actually work Ben? Is it cached locally on my computer or stored to my account? The reason I ask is, when I look on my phone, it doesn't seem to pick up my default that I set on my computer.

I changed the default map background. The default is now a background that I made, but it only goes to zoom level 14. The satellite background goes to zoom 19. You can switch the background by using the menu button in the upper left corner. The old default is "ArcGIS Satellite with Labels."