This study compares dialogic behavior in asynchronous course forums from blended learning environments with "non"-mandatory student participation at a campus-based college and at a distance education, Open University. The goal is to document similarities and differences in students' and instructors' dialogic behavior that occur in two similar instructional resources used in two dissimilar learning environments. Quantitative content analysis, derived from the "Community of Inquiry" model, was performed on a year-long course forum from the college. These data were compared with composite data obtained previously from 50 Open University course forums. Findings showed that the dialogic behavior in the college forum differed greatly from the dialogic behavior exhibited in distance education forums. Specifically, the frequencies of "social presence", "teaching presence" and "cognitive presence" in the forums differed significantly. However, high frequencies of social presence coupled with low frequencies of cognitive presence at both institutions raise doubts regarding the popular assumption that deep and meaningful learning occurs in asynchronous course forums. (Contains 9 tables and 1 figure.)