Media multitasking (MMT) is now a common way to engage with media. Flexibility in devices and content allow people to actively manage their attention but also to become distracted from their original goals. Advertising messages are commonly delivered within this environment, yet much advertising research still studies advertising under full attention. Research on MMT (also called multiscreening, dual-screen, cross-screen, divided attention, and social TV) can provide some guidelines on what to consider and expect for messages exposed during multitasking. However, there are also several areas of caution and many unknowns. We discuss theories used to study multitasking effects, theories that might provide some new directions, and the importance of identifying elements related to the audience, tasks, medium, and ad. Advertising effects that were established under direct attention should be revisited within a multitasking context, and we highlight areas that could be particularly affected by multiple media use. Overall, (in)attention as context for message effects will help us to better understand and predict how advertising is perceived in the new normal way of engaging with media.