This paper gives a description of an annotation scheme for annotating a corpus of computer-mediated communication in Hindi (CO3H) with certain semantic, pragmatic and situational features. The annotation scheme is based on the theory of register analysis, where it is assumed that a registeral difference entails difference in certain linguistic features. It adapts and integrates the annotation schemes of sense annotation in the Penn Discourse Treebank and dialogue act annotation of DIT++ within this larger registeral framework. The situational and linguistic features that will be used to annotate the corpus for PoRT is described in the paper, along with some proposed labels for these features.