From the Email Notification section you can enable and disable different email notifications. These options only affect the specific account that you are logged on with. Each administrator can set these options as they like.
To get to the Email Notification section you need to select the "Preferences & Logout" tab.
The "Tenant Notification" button allows you enable and disable email notification for each tenant. Disabling email for a specific tenant means you will not get any emails notifications from that tenant.
See: Tenant Accounts