Stealth marketing is the set of marketing communication practices that diffuse a positive information or message about the brand or its products without consumers knowing that the message emanates from the brand or its agency or has been paid.
Stealth marketing has applications on the Internet but also in the street where, for example, actors may pass for mere early adopters of a new technology product in trendy places visited regularly by the target.
Undisclosed product placement or endorsement are also forms of stealth marketing and undercover marketing is an extreme kind of.
Sometimes, when stealth marketing practices are identified by consumers or observers, the practice can turn against the brand.
Stealth marketing practices can sometimes cause commercial legal code compliance issues.
On a nearby field, also see guerrilla marketing.