Consumers have become increasingly savvy about technology in recent years, and many of them ignore Web ads during online activities. In this context, measuring advertising effects based on the traditional cognitive models of information processing may undervalue the effectiveness of Web ads. This study experimentally examined the effects of unconscious processing of Web ads by manipulating the level of attention paid to the ad (directed vs. nondirected attention). Online advertisers should be encouraged by the findings of this study. The results suggest that, upon exposure to Web ads, consumers experience priming caused by implicit memory and build a more favorable attitude toward the advertised brand regardless of the levels of attention they paid to the advertisements. Furthermore, those who unconsciously processed Web ads did not remember seeing the ad explicitly, but they were more likely to include the advertised brand in the consideration set than those who had no exposure.