Scientific discourse occurs both in the academic literature and, increasingly, on the Web. What is discussed in the literature influences what is discussed on the web, and the reverse. However, the study of this discourse has largely been isolated based on medium either using bibliometrics for academic literature or webometrics for Web-based communication. In this work, the science blog aggregator Researchblogging.org is used to enable the study of scientific discourse on the Web using bibliometric techniques, in particular, keyword and citation similarity maps. The study focuses on a set of 295 chemistry blog posts about peer-reviewed research. Based on bibliometric maps, we provide evidence that scientific discourse on the Web is more immediate, contextually relevant and has a larger non-technical focus than the academic literature.