“…In this case, crowdsourcing is used to obtain a great number of labels quickly and inexpensively, as is the case of Hovy et al (). In relation to the problems solved by these applications, we find that most of them are related to open challenges in natural language processing (for an introduction to some of them, we refer the reader to Hirschberg and Manning ()): sentiment analysis of online media (Brew, Greene, & Cunningham, ; Salter‐Townshend & Murphy, ); joke's humor classification (Costa et al, ); temporal relation classification (Ng & Kan, ); word sense (Passonneau et al, ); marketing messaging classification on Twitter (Machedon et al, ); part‐of‐speech tagging (Hovy et al, ); identifying fake Amazon reviews (Fornaciari & Poesio, ); sequence labeling (Nguyen, Wallace, et al, ; Rodrigues et al, ); estimation of discourse segmentation (Huang et al, ); emotion estimation from narratives (Duan et al, ); crowdsourced translation (Yan et al, ); entity disambiguation (Li, Yang, et al, ; Nguyen, Duong, et al, ; Zhou et al, ); topic models (Liu et al, ; Rodrigues et al, ); personal assistants (Shin & Paek, ; Yang et al, ); corpus creation for Arabic dialects (Alshutayri & Atwell, ); and context sensitive tasks (Fang et al, ).…”