The author analyses computer chat as a form of communication. While some forms of computer-mediated communication (CMC) deviate only marginally from traditional writing, computer chat is popularly considered to be written conversation and the most -oral- form of written CMC. This book systematically explores the varying degrees of conversationality (-orality-) in CMC, focusing in particular on a corpus of computer chat (synchronous and supersynchronous CMC) compiled by the author. The author employs Douglas Biber's multidimensional methodology and situates the chats relative to a range of spoken and written genres on his dimensions of linguistic variation. The study fills a gap both in CMC linguistics as regards a systematic variationist approach to computer chat genres and in variationist linguistics as regards a description of conversational writing."