Consumer-to-consumer (C2C) (or citizen-to-citizen) electronic commerce involves the electronically-facilitated transactions between consumers through some third party. A common example is the online auction, in which a consumer posts an item for sale and other consumers bid to purchase it; the third party generally charges a flat fee or commission. The sites are only intermediaries, just there to match consumers. They do not have to check quality of the products being offered.
Consumer-to-consumer (C2C) marketing is the creation of a product or
service with the specific promotional strategy being for consumers to
share that product or service with others as brand advocates based on
the value of the product. The investment into concepting and developing a
top of the line product or service that consumers are actively looking
for is equatable to a Business-to-consumer (B2C) pre launch product
awareness marketing spend.