When an email address is entered without a constituent attached to the Sales Order, the email address is stored on the Sales Order record. You can easily access the email address using a Sales Order query. 
  1. Go to Analysis > Information Library 
  2. Click Add an ad-hoc query 
  3. Select the source view of Sales Orders and click OK
  4. From the middle column, drag Email to Include records where. Set this to be not blank. Your field will appear like this: Email is not blank. To view the email address, also drag Email to Results fields to display. 
  5. To find only anonymous orders with an email address, from the left column, highlight the Constituent node. From the middle column, drag a field like Name or Lookup ID to Include Records Where. Set this to be blank. Your field will appear similar to this one: Constituent\Name is blank. Your final query will look similar to this one: 
    User-added image
  6. (Optional) If you would like to see if an email address is associated with multiple orders:
    1.  In Results fields to display highlight Lookup ID and click the Sigma sign. Check the box to COUNT the Lookup ID. This will count each unique sales order by email address:                                   
      User-added image
    2. On the Set sort and group options tab, drag COUNT(Lookup ID) to the Sort records by box. Choose to sort this by descending (Z-A) to see the email addresses associated with the most orders first. 
    3. Your results will appear like this:                      
      User-added image
  7. On the Set save options tab, save your query to access later.