We recently rolled out the capability for customers to add comments to an order. During checkout, they have the option to add a few words regarding their order.
You will see these comments on the Event Roster in the comments field. You will also see them in the relevant order. There, you can edit comments just as before.
AN IMPORTANT THING TO KNOW: When you edit an order's comment, only the most recent comment will show on the roster. If you need to add to a customer comment, be sure to copy the entire comment and then add to it. This way the customer comment is preserved on the roster.