Sun, T., Zhang, M. and Mei, Q. 2021. Unexpected Relevance: An Empirical Study of Serendipity in Retweets. Proceedings of the International AAAI Conference on Web and Social Media. 7, 1 (Aug. 2021), 592-601. DOI:https://doi.org/10.1609/icwsm.v7i1.14435.