Design Patent
What the article fails to make clear is what is meant by a design patent (or patented design as it is referred to in the text). A design patent is the US equivalent of what most other countries refer to as a Registered Design and is all about the physical appearance and characteristics of the item, not how it functions. A utility patent covers the latter, and is generally seen as the more important form of intellectual property for technology companies, since the outside appearance of a product can easily be changed to avoid infringing, whereas re-designing the functionality so that it doesn't infringe may be either expensive or technologically impossible in the short term.