Boosters are rules within a Marketing Cloud Personalization recipe that promote or demote items in the recommendation pool based on specific criteria. A key use case for boosters is to leverage a visitor's affinity scores. For example, if a visitor shows a high affinity for a particular brand or category, a booster can increase the ranking of items with that brand or category attribute, making them more likely to be recommended. This directly ties the visitor's calculated affinity to the recommendation output.

A. Exclusion: Exclusions remove items entirely from recommendations; they do not use affinity scores to adjust the ranking of items.

B. Ingredients: Ingredients are the base algorithms that generate the initial list of recommendations, not the component that applies affinity-based scoring.

D. Variation: Variation rules are used to ensure diversity in recommendations (e.g., by category), not to apply affinity scores.

Salesforce Help. (2024). Recipe Components. Salesforce, Inc. Retrieved from https://help.salesforce.com/s/articleView?id=sf.mcpersrecipecomponents.htm&type=5. See the "Boosters" section, which states, "Boosters promote or demote items... based on the affinity a user has for an item attribute."

Salesforce Help. (2024). Configure a Booster in a Recipe. Salesforce, Inc. Retrieved from https://help.salesforce.com/s/articleView?id=sf.mcpersconfigurebooster.htm&type=5. This guide details the process, showing how to select "User Affinity" as the basis for the booster rule.