Since privacy issues are becoming important with growth of the video surveillance, many tools are proposed for protection of personal privacy in the video. However, little is understood regarding the effectiveness of such tools and their effect on the underlying surveillance tasks. In this paper, we propose a subjective evaluation methodology that compares several popular privacy protection techniques applied to typical indoor surveillance video. We identify and analyze the tradeoff between the privacy preservation of these tools and the intelligibility of activities in the resulted surveillance video.