Facebook Insights can provide you with at-a-glance information about products that have been "Liked," user demographics, and other key metrics.
Once you have added a Facebook Application ID for your store and published your store pages, Facebook Insights can be enabled for your store's top-level domain. Your pages must be published after entering the ID in either the Design Wizard or Store Editor, or Facebook will not be able to verify the Facebook Application ID.To enable Facebook Insights:
Go to the Facebook Insights page and sign in to your Facebook account. (The account you used when obtaining your Facebook Application ID.)
Click on "Insights for your domain." If you do not see an "Insights for your domain" link, you should instead see an "Insights for your Website" link.
In the pop-up that opens, you will see a Domain field. Enter your store domain into this field (e.g., mystoredomain.com), then choose the application you created to generate your Facebook Application ID using the "Link With" drop-down list.
Click the "Check domain" button.
Facebook Insights should now be ready to use. To learn more about Facebook Insights and what it can be used for, please see the Facebook Insights help center.