In this study, we extend previous work on instructors' use of technology by examining how students' perceptions of teacher credibility and affective experience differ depending on how frequently instructors use two common forms of instructional technology: PowerPoint, which is typically used "inside" the classroom; and email, which is typically used "outside" the classroom. Participants read vignettes that randomly manipulated the amount of each technology used by the instructor. Results revealed a positive association between instructor email use and students' affective experience. For teacher credibility, a more complex pattern emerged, with instructors who combine rare email use with limited PowerPoint use suffering lowest evaluations on teacher credibility. Thus, effective use of classroom technology should avoid ambiguity or communicating a dismissive attitude toward students, who generally seem to prefer a high degree of technological integration in their courses.