Here is a brief overview on how to use the customer panel inside your control panel. It helps you manage all the details of your customers and to see a list of all their transactions and registrations. These customers are recorded separately from each product. So you would have a unique customer panel for online giving as you would have for event registration.
When managing a product, click on the Customers Icon near the top of the page. You'll get a alphabetic listing of all your customers. You can hit search to find a unique person, or you can hit export to download the entire list.
Click on Details to view the customer details. You'll see on the left the general details for the customer including name, address and email. On the right side, you'll see a list of recent campaigns that they have registered for. Near the bottom of the page, you'll see a transaction history for this customer (including all attempts). If someone has recurring transactions, you'll see the listing of those transactions there.
From this screen you can do a couple convenient things.
1) You can update the customer's details easily. This will update all their other registrations and transactions with this updated information.
2) You can quickly go to any registration or transaction attempt. You don't need to hunt and search for them in the campaigns.
Having this information linked from here will save you lots of time in locating someone when you have dozens of campaigns and events.