  As large-scale graphs become more widespread, more and more computational
challenges with extracting, processing, and interpreting large graph data are
being exposed. It is therefore natural to search for ways to summarize these
expansive graphs while preserving their key characteristics. In the past, most
graph summarization techniques sought to capture the most important part of a
graph statistically. However, today, the high dimensionality and complexity of
modern graph data are making deep learning techniques more popular. Hence, this
paper presents a comprehensive survey of progress in deep learning
summarization techniques that rely on graph neural networks (GNNs). Our
investigation includes a review of the current state-of-the-art approaches,
including recurrent GNNs, convolutional GNNs, graph autoencoders, and graph
attention networks. A new burgeoning line of research is also discussed where
graph reinforcement learning is being used to evaluate and improve the quality
of graph summaries. Additionally, the survey provides details of benchmark
datasets, evaluation metrics, and open-source tools that are often employed in
experimentation settings, along with a detailed comparison, discussion, and
takeaways for the research community focused on graph summarization. Finally,
the survey concludes with a number of open research challenges to motivate
further study in this area.
