  We present our view of what is necessary to build an engaging open-domain
conversational agent: covering the qualities of such an agent, the pieces of
the puzzle that have been built so far, and the gaping holes we have not filled
yet. We present a biased view, focusing on work done by our own group, while
citing related work in each area. In particular, we discuss in detail the
properties of continual learning, providing engaging content, and being
well-behaved -- and how to measure success in providing them. We end with a
discussion of our experience and learnings, and our recommendations to the
community.
