Educational blogs are currently gaining in popularity in schools and higher education institutions, and they are widely promoted as collaborative tools supporting students' active learning. However, literature review on educational blogging revealed a lack of a complete and consistent framework for studying and assessing students' engagement and the impact of blogging on students' learning. This study reports on the application of an analysis framework for evaluating blogging learning activities, based on two well-documented models, those of "Community of Inquiry" ("CoI") and "Social Network Analysis." The framework proposed is examined through an empirical study involving 21 K-9 students, coming from two classes, in Greece. This investigation shed light into the different ways of students' engagement in a blog-based project, namely their social and cognitive presence that supported the development of a CoI and learning. The results suggest that the students, through their different roles in the blog, achieved higher thinking and cognitive levels.