How influence on marketing: Every public has an impact on marketing activities of the company. They can affect positively or negatively. As a marketing manager you have to consider all the public related with your business.
Example: Suppose a company produces a product but pollutes the environment. Environmentalist group of that locality are raising voice against the company, so company will not be able to conduct its operation at that locality. So citizen action publics are influencing the marketing functions of that company.
In India coca cola was forced to withdraw its business due to the pressure of citizen action publics. They wanted to know about the formula of preparing coca cola. But the company did not agree to disclose its formula. At last it withdrew its operation from India.