The enthusiasm for adopting social media technologies should be tempered by a critical, empirical understanding of how they facilitate an effective learning envionrment. This study analyzed blog use in two graduate-level university courses, specifically identifying reflective learning markers in 279 blog entries. This analysis was deepened with follow-up interviews of several top bloggers. The reflective bloggers were characterized as being comfortable with their audience, having a deeper thought process, enjoying the interaction, and progressing well throughout the semester. Our results suggest guidlines for effective use of blogging in the classroom to support reflective learning.