Choose the customer group that new customers get when Junipeer creates them in Magento.
Choose from the list. It shows the customer groups in your Magento.
You can leave it empty.
Good to know
For new company customers, see Default Company Customer Group.
If the list is empty, check that Magento is connected. An empty list almost always means the connection, not the setting.
If a value is missing, create it in Magento first, then click Clear Cache on the settings page so the list is refreshed.