This study investigates differences in the language and discourse characteristics of course blogs and traditional academic submissions produced in English by native (L1) and advanced second language (L2) writers. One hundred and fifty-two texts generated by 38 graduate students within the context of the same Master's level course were analysed using Coh-Metrix indices at the surface code, textbase and situation model levels. The two text types differed in their lexical sophistication, syntactic complexity, use of cohesion and agency. Overall, the traditional course assignments were more formal, lexically sophisticated and syntactically complex, while the blog posts contained more semantic and situational redundancy, resulting in higher readability, and communicated a clearer sense of agency. There were also reliable differences between the textual artefacts generated by the L1 and L2 writers, one of which was a more traditional impersonal academic style of the L2 texts. Although no interaction was observed between the two independent variables in the Coh-Metrix analyses, an additional analysis of human ratings showed that the blog posts were rated lower on the use of language than traditional assignments for the L2, but not L1, writers. Limitations of the computational text analysis and pedagogical implications of the findings are considered.