Emoji have become an integral part of modern digital communication. This chapter takes a closer look at this type of ‘iconographetic communication’, from a linguistic perspective. Today’s digital communication in which emoji are added to written language is compared to older forms of communication where pictograms accompanied texts. In addition to this historical perspective, a survey on the semiotic and semantic aspects of emoji are presented. The focus of the present chapter is on the functions of emoji in digital communication in which the so-called referential function (namely, that emoji are a part of the respective proposition) is of particular importance. Moreover, other various functions of emoji are explained, using examples from WhatsApp, Twitter, Instagram, and Facebook.