Day parting in advertising refers to the practice of dividing the day into specific time periods or "parts" and targeting ads to audiences during those periods. By identifying the times of day when specific audience segments are most likely to be engaged, advertisers can optimize their ad campaigns to reach the right audience at the right time.

For example, a breakfast cereal company may want to target their ads to families with children during the early morning hours when people are getting ready for school and work. A restaurant chain may want to target their ads to hungry consumers during the lunch hour. A beverage company may want to target their ads to people relaxing in the evening after a long day.

Day parting can be used across a variety of advertising channels, including television, radio, and digital advertising. In digital advertising, day parting can be especially effective because it allows advertisers to target specific time periods with precision and adjust their ad campaigns in real-time to maximize performance.

Day parting can be an effective way to increase the relevance and effectiveness of an ad campaign, especially when combined with other targeting methods such as geographic targeting, demographic targeting, or interest targeting. By delivering the right message to the right audience at the right time, advertisers can improve their ROI and achieve their marketing goals more effectively.