On 10/8/08, Arch Rock of San Francisco, CA, a WSN (Wireless Sensor Networking) technology provider submitted CAP, (Compact Application Protocol), for consideration by the IETF (Internet Engineering Task Force) standards body as an RFC standard. What is CAP? CAP is essentially an adaptation of the ZigBee application-layer profiles to enable these profiles to operate directly and transparently over an Internet Protocol networking layer. Although Arch Rock has put only a muted public relations effort behind the introduction, ABI Research believes CAP is an important milestone on the path from completely proprietary WSN technology, to open, horizontal WSN deployments that integrate seamlessly into the wider IP world. This Insight will provide a brief description of CAP and its benefits, then discuss the evolution of WSNs toward increasingly open deployments.