  Sharing ideas through communication with peers is the primary mode of human
interaction. Consequently, extensive research has been conducted in the area of
conversational AI, leading to an increase in the availability and diversity of
conversational tasks, datasets, and methods. However, with numerous tasks being
explored simultaneously, the current landscape of conversational AI becomes
fragmented. Therefore, initiating a well-thought-out model for a dialogue agent
can pose significant challenges for a practitioner. Towards highlighting the
critical ingredients needed for a practitioner to design a dialogue agent from
scratch, the current study provides a comprehensive overview of the primary
characteristics of a dialogue agent, the supporting tasks, their corresponding
open-domain datasets, and the methods used to benchmark these datasets. We
observe that different methods have been used to tackle distinct dialogue
tasks. However, building separate models for each task is costly and does not
leverage the correlation among the several tasks of a dialogue agent. As a
result, recent trends suggest a shift towards building unified foundation
models. To this end, we propose UNIT, a UNified dIalogue dataseT constructed
from conversations of existing datasets for different dialogue tasks capturing
the nuances for each of them. We also examine the evaluation strategies used to
measure the performance of dialogue agents and highlight the scope for future
research in the area of conversational AI.
