The bare minimum anyone must adhere to is the law (government regulation and legislation). In almost every profession, there is then a code/statement of ethics that
practitioners are expected to adhere to: the one for the American Marketing Association, for example, can be found
here. These codes represent the minimal acceptable behaviors within the field. Organizations and companies often have their own code as well. Above all of those resides the ethics of the individual - what will they do when confronted with a gray area. From a Biblical perspective,
Proverbs 22:1 speaks to this better than any other verse.
Social Responsibility was addressed by Milton Friedman in his landmark paper, "The Social Responsibility of Business is to Increase its Profits" in the New York Times (September 13, 1970). A copy of it can be found
here. While the entire paper is wonderful, to me the best issues can be found early on in the first, second and fourth paragraphs.