Human vision is sensitive to salient features such as motion. Therefore, animation and onset of advertisements on Websites may attract visual attention and disrupt reading. We conducted three eye tracking experiments with authentic Web pages to assess whether (a) ads are efficiently ignored, (b) ads attract overt visual attention and disrupt reading, or (c) ads are covertly attended with distraction showing up indirectly in the reading performance. The Web pages contained an ad above a central text and another ad to the right of the text. In Experiments 1, 2, and 3A the task was to read for comprehension. Experiment 1 examined whether the degree of animation affects attention toward the ads. The results showed that ads were overtly attended during reading and that the dwell times on ads were the longest when the ad above was static and the other ad was animated. In Experiments 2 and 3, the ads appeared abruptly after a random time interval. The results showed that attention (i.e., the time when the eyes first entered an ad) was related to the ad onset time. This happened especially for the ad to the right, indicating that ads appearing close to the text region capture overt attention. In Experiment 3B the participants browsed the Web pages according to their own interest. The study demonstrated that salient ads attract overt visual attention and disrupt reading, but during free browsing, ads were viewed more frequently and for longer time than during reading. (Contains 7 figures, 8 tables, and 3 footnotes.)