Some lawyers not trained in business still miss the distinction between various terms used in conjunction with the general term “marketing.” Marketing is a process not an activity. It consists of many things that together make up marketing – including public relations and advertising, which simply put are tools of marketing.
The main difference between “PR” and “advertising” is that the former is free advertising (except for the PR agency costs involved, if any) in the form of publicity (being quoted in articles, part of a feature articles, etc.) and are usually written by someone else. Advertising, on the other hand, is paid for publicity in the form of ads. Clearly, the former is more valuable and credible than the latter.
Marsha Friedman, CEO of EMSI, a public relations firm, has an article on her web site, that I came across via LinkedIn that futher clarifies the distinctions between these terms. Take a look.