As broadband access to the Internet becomes pervasive, the need for a 24 hours a day, seven days a week (24x7) interface within the client devices, requires a level of sophistication that implies agent technology. From this situation we identified the need for a user-proxy++, something we have termed the Digital Self that acts for the user gathering appropriate information and knowledge, representing and acting for them when they are off-line. With these notions in mind we set about defining an agent architecture, sufficiently complex to deal with the myriad aspects of the life of a busy time-poor modern user, and we arrived at the Shadowboard architecture. For the theory, for the model of mind, we drew upon the Psychology of Subselves, a modern strain of Analytical Psychology. For the computation engine we drew upon Constraint Logic Programming. For the hundreds of sources of sub-agency and external intelligence needed to enact a Digital Self within the 24x7 Internet environment, we drew upon the Web Services paradigm. This paper presents the theory, the architecture and the implementation of a prototype of the Shadowboard agent system.