Online instructional videos are ubiquitous, but it is difficult for instructors to gauge learners’ experience and their level of comprehension or confusion regarding the lecture video. Moreover, learners watching the videos may become disengaged or fail to reflect and construct their own understanding. This paper explores instructor and learner perceptions of in-video prompting where learners answer reflective questions while watching videos. We conducted two studies with crowd workers to understand the effect of prompting in general, and the effect of different prompting strategies on both learners and instructors. Results show that some learners found prompts to be useful checkpoints for reflection, while others found them distracting. Instructors reported the collected responses to be generally more specific than what they have usually collected. Also, different prompting strategies had different effects on the learning experience and the usefulness of responses as feedback.