A customer segmentDetermines the target audience (such as "users from Los Angeles") for a promotion. Within a campaign, promotions are applied to whatever customer segments are associated with the same campaign. Members of the customer segments are defined in static groups, or you can use the Expressions Engine to create a dynamic group whenever you run a promotions. You can create an expression that includes customers whose home city is Los Angeles so that when a LA user registers on the site, the user becomes part of the target customer segment. determines the target audience for promotions or campaigns. Within a campaignCommerce: a set of related components and activities used for promotions. A campaign organizes marketing activity and is associated with discounts (promotions), customer segments, and markets., a promotion is applied to whatever customer segments are associated with the same campaign.
You can define the member groups of customer segments or you can use expressions to create dynamic groups whenever you run a promotion. For example, you can have a customer segment that targets users from the Los Angeles area, then create an expressionCommerce: customizable conditions that let users extend the marketing system -- promotions, customer segments, and policies rely on expressions. For example, to set a promotion for 40% off Item X, use Catalog ID for Item X and Reward of 40%. that includes the customers whose home city is Los Angeles. So when a visitor from Los Angeles registers on the site, the visitor immediately becomes part of the target customer segment.
You can create a customer segment and manually assign specific contacts to the customer segment, or you can use conditions to apply rules that automatically make selected customers become part of the customer segment.