Dialogue systems powered by conversational artificial intelligence (AI) have never been so popular. Interacting with computer through languages reveals a more natural interface to give orders and acquire information---just like human communication. Due to promising potential as virtual assistants and/or social bots, major NLP, AI and even Search & Mining communities are explicitly calling-out for contributions of conversational studies. Learning towards real conversational intelligence is a trip to Mars; perhaps we are yet on Earth. We have achieved substantial progress from recent research outputs. Still we have major obstacles to overcome. In this paper, we present an overview of progress and look forward to future trends so as to shed light on possible directions towards success.