I notice on Magento 1.7.0.2 and 1.9.2.4, some customer accounts which are duplicated.
However one is defined on the default store view (id: 1 => "Default Store View") and the second one is defined on "Admin" (id: 0 => "Admin").
The store view "Admin" is not visible from magento backend but exist in database.
What is this? How it possible? What does this means?