In this article, the authors answer the call of the IText manifesto to use ITexts to explore fundamental issues of writing, describing instant messaging (IM) as a form of interactive networked writing (INW) and showing how IM writers discursively construct contexts. Specifically, they argue that writers use (a) deixis to build and maintain material contexts and (b) intertextuality to construct sociocultural contexts. Four intact IM transcripts were coded for instances of four kinds of deixis—space, time, person, and object—and for instances of intertextuality. Results showed that IM writers use all four kinds of deixis and that deictic elements made up almost 10% of the total words of the transcripts. In addition, two kinds of intertextual elements— direct quotation and cultural referents—were used to invoke, build, and sometimes undermine social and cultural contexts. The authors also discuss some of the material affordances and constraints of writing and conclude by arguing that INW is literally dialogic.