How far we've come: Impact of 20 years of multimedia information retrieval

This article reviews the major research trends that emerged in the last two decades within the broad area of multimedia information retrieval, with a focus on the ACM Multimedia community. Trends are defined (nonscientifically) to be topics that appeared in ACM multimedia publications and have had a significant number of citations. The article also assesses the impacts of these trends on real-world applications. The views expressed are subjective and likely biased but hopefully useful for understanding the heritage of the community and stimulating new research direction.