Researchers have recognized the need to pay attention to negative aspects and non-use of social media services to uncover usage barriers and surface shortcomings of these systems. We contribute to these efforts by analyzing comments on posts related to Facebook on two blogs with a technically savvy readership: Slashdot and Schneier on Security. Our analysis indicates that technically savvy individuals exhibit notably large negative sentiment toward Facebook with nearly 45% of the 3,000 reader comments we coded expressing such views. Qualitative coding revealed Privacy and Security, User Experience, and Personal Disposition as key factors underlying the negative views. Our findings suggest that negative sentiment is an explicit higher level factor driving non-use practices. Further, we confirm several non-use practices reported in the literature and identify additional aspects connected to recent technological and societal developments. Our results demonstrate that analysis of user generated content can be useful for surfacing usage practices on a large scale.