Lines are used to execute media buying strategies within a Campaign. While the Campaign organizes a group of strategies under a shared budget and flight structure, the Line controls the execution of media delivery and spend.

Each Campaign must contain at least one active Line in order to deliver impressions. Multiple Lines can be created under a single Campaign to separate strategies by inventory source, optimization model, audience, geography, device, bidding approach, or media channel.

Depending on Campaign configuration, settings such as targeting, creatives, audiences, pixels, pacing, and frequency controls may either be managed globally at the Campaign level or configured independently at the Line level. Campaign-level settings act as shared controls and additional filters across all associated Lines.

Because the Line controls media execution, proper setup of targeting, pacing, bidding, and inventory selection is critical to campaign delivery and performance optimization. When targeting is applied at both the Campaign and Line levels, targeting is evaluated using an intersection model, meaning impressions must satisfy all conditions applied at both levels in order to be eligible to serve.

Campaign-level targeting should be used for settings that apply universally across all Lines, while Line-level targeting should be used for strategy-specific execution. For example, a Campaign may broadly target the United States, while individual Lines target specific states, DMAs, ZIP codes, audiences, inventory types, or devices. If targeting settings conflict between levels, impressions may become ineligible and delivery may be limited.

Best Practices:

• Use Campaign-level targeting only for settings that should apply universally across all Lines.
• Use Line-level targeting for strategy-specific targeting and optimization.
• Apply targeting at one level whenever possible unless the intent is to intentionally narrow eligible inventory through intersection filtering.