1. What separates Web companies known for their customer service is not only their prices, but also the availability and promptness of their staff—via both e-mail and phone—in addressing customers' concerns. What's more, these companies typically empower their front-line reps to resolve problems at their discretion, rather than having to run everything by a manager. This saves time for both the customer and the company.
2. A common strategy to obtain feedback is simply to ask for it. For example, while browsing DHS.gov, a pop-up sometimes appears asking you to complete a quick survey. After you make a purchase from Google Checkout, you'll get an e-mail asking you to rate the transaction. Sellers on Amazon can e-mail you a request to leave feedback on their profile.
3. When you add an item to your cart on VistaPrint.com but don't check-out, if you're logged-in to the site, the company will e-mail you a reminder about your pending purchase. This is a great idea--though VistaPrint does it repeatedly, which I find obnoxious.