Detailed statistics are provided for any email sent through the GroupSpaces interface to Pro subscribers and above. Statistics cannot be provided for emails sent to a list from your own email account.
Visit the Sent Emails section under your Emails tab and click on the Delivery Report button to view who has already opened* your email and if any emails bounced. Clicks shows you the list of links which your e-mail contained as well as the number of times each link was clicked on.
A Note on Open Rates: The opened rate is the number of people who opened the e-mail AND loaded images. This is the only way it is possible to track opens, but it means the 'true' count of people who read your e-mails is often a lot higher than the displayed count, due to some e-mail clients automatically blocking images, or people reading e-mails in preview mode.