In this digital era, students tend to write more for non-academic purposes on social media platforms by using informal language. Consequently, they become familiar with the informal writing style and use non-academic language in academic writing. This research, therefore, aims to discover 1) what are the results of using the social media text-based exercises developed by the researchers in promoting university students' knowledge of non-academic and academic English language, and 2) what are the students' attitudes toward the use of social media text-based exercises. The instruments included four sets of social media text-based exercises, a pre-test, a post-test, and an open-ended questionnaire. Participants were 96 third-year English major students enrolling in the Academic Writing course, sections 1, 2, and 3 in the 1(st) semester, the academic year 2021 of a university in Thailand. The findings showed that the social media text-based exercises were effective in promoting the students' knowledge of the non-academic and academic language. Questionnaire respondents expressed great attitudes toward the exercises. They believed the materials enabled them to analyze and identify distinct features of the registers in non-academic and academic writing. Additionally, they mentioned that learning through the exercises was interesting, enjoyable, and understandable. The study also provided suggestions for improving the exercises.