Halliday & Matthiessen (2014: 42):
Technological advances have continued to enhance the potential of both phonic and graphic channels, and to enable mixed channels (cf. Halliday, 2008: 140–141). Importantly, mobile and web-based technologies (for hardware and software) have changed the possibilities of ‘sharing’ in rather dramatic ways, with a whole host of new options like e-mail messages, text messages, blogs, tweets and other formats associated with social media, as investigated and discussed by Macnamara (2010). As a result, the distinction between the private sphere of ‘sharing’ values and opinions and the ‘public’ sphere of exploring them has become blurred.