The current study investigates the applications of the pinyin input system, a Chinese word processing method, for writing on Facebook in order to help CFL (Chinese as a foreign language) learners from two Irish universities to improve their handwriting in Chinese characters on paper. The data were collected from writing activities conducted over 12 weeks on Facebook, which was the platform for the research, and then from an exam question written on paper. Analysis of the data show that inputting Chinese in pinyin on Facebook did not significantly contribute to either the number of characters used or the lexical variation of the participants' handwriting on paper. However, accuracy in the characters used was significantly higher on Facebook than in those written with conventional pen and paper, since by using the pinyin input system, the learners could use their phonological knowledge of the characters and then needed only to recognise the correct characters. Two unexpected findings emerged from the data: one was that the participants' engagement with the social affordances of Facebook was limited; the second was the use of machine translation when writing online. The study provides invaluable insights into the possibilities of applying social networking and machine translation in the language classroom for CFL learners with both low and high command of the Chinese language.