Final answer:
Harley-Davidson motorcycle owners, Jeep event attendees, and Star Trek "Trekkies" are examples of consumption subcultures, which serve as reference groups that influence member behaviors and community engagement around shared interests in specific brands or products.
Step-by-step explanation:
Harley-Davidson motorcycle owners who join a Harley group, Jeep owners who attend events sponsored by Jeep, and Star Trek "Trekkies" are all examples of consumption subcultures. These are groups of individuals who share an affinity for a specific brand or type of product, which in turn often influences their social behaviors and the community they engage with. Subcultures can occasionally be formed around shared experiences, interests, or prominently, around a specific consumer product, as is the case with Harley-Davidson enthusiasts or Jeep owners. Such groups serve as reference groups for their members, providing standards for behavior within the context of their shared interests.