• Information integrated from eCommerce: "shopping cart" status, order details, and credit-card payment status

• Information integrated from the accounting system: order history, invoices, and payments

• Information integrated from the manufacturing/ERP system: shipments, serial numbers, inventory, backlog, parts availability, return merchandise authorization (RMA) numbers, reverse-logistics information, and warranty information

• Information integrated from engineering: defect reporting/tracking, resolutions, technical bulletins, patches, licenses, and repair/rework status

As most of these data elements don't change very often, you can probably get away with a periodic batch update in most cases. However, probably 10 percent of the data changes frequently, so some real-time integration will be required. While SFDC's APIs and 3rd-party integration connectors fully support closed-loop integration, there are implementation and maintenance costs involved. The depth of integration you use (including, for example, providing a login frame to external systems within an SFDC tab) is really a business decision, and most of our clients choose their integration approach on a screen-by-screen basis.