The traditional definition of a corporate network

In today’s computing world, the traditional definition of a corporate network no longer applies, due to the increased use of cloud computing services and mobile computing devices. In your own words, describe how Network Security Monitoring fits into this new paradigm and, with these other services and devices being used within a company, who should be responsible for securing and monitoring the network and devices beyond the corporate network boundary? Is your concept feasible? Is it already a reality for some organizations?