Abstract
Social media publicity has become an important way for the official tourism agency to promote the city image and interact with the public. In order to explore the linguistic devices that support tourist city publicity, a corpus-based comparative study is conducted on the use of metadiscourse and identity construction in Facebook posts on the public pages of the city Xiamen in China and Sydney in Australia. The corpus consists of 344 posts with a total of 12, 175 words on the page of Xiamen and 315 posts with a total of 12, 319 words on the page of Sydney collected over the same 1-year time span. Combining the statistical results of metadiscourse use and identity types with the analysis of specific examples, it is concluded that both posters use three categories of metadiscourse to construct the identities of introducer, inviter and evaluator for the purpose of promoting good city image and forming good interaction with the public. The differences in the frequencies of metadicourse and identity occurrences in the two corpora suggest different focuses on city publicity. This study has implications for the writing of tourist city publicity posts as well as raising posters' awareness of employing metadiscourse to construct identity and build rapport with readers so as to enhance the impact of the tourist cities.