  Building dialogue systems that naturally converse with humans is being an
attractive and an active research domain. Multiple systems are being designed
everyday and several datasets are being available. For this reason, it is being
hard to keep an up-to-date state-of-the-art. In this work, we present the
latest and most relevant retrieval-based dialogue systems and the available
datasets used to build and evaluate them. We discuss their limitations and
provide insights and guidelines for future work.
