doi dblp Opico: A Study of Emoji-first Communication in a Mobile Social App Sujay Khandekar | Joseph Higg | Yuanzhe Bian | Chae Won Ryu | Jerry O. Talton | Ranjitha Kumar Companion of The 2019 World Wide Web Conference, WWW 2019, San Francisco, CA, USA, May 13-17, 2019