Public relations, marketing, and advertising are often confused. Each has similarities, overlaps, and distinct differences. Ideally, a combination of the three disciplines is used to build goodwill and grow an organization.
 
In a nutshell:
 
Public relations is the function of establishing and maintaining mutually beneficial relationships among various publics (i.e., between an organization and its customers, employees, and shareholders). It is two-way communication among publics: listening, sharing, offering information/ feedback, adjusting communication and organizational objectives, products, services, branding, etc., based on feedback. Public relations is usually centered on awareness-building, attitude-influencing, and/or action-inducing activities.

A sub-discipline of public relations is media relations/publicity – the practice of pitching news stories in publications, on broadcasts, and on Web sites – in order to build awareness, buzz, etc. Publicity is uncontrolled in the sense that once messaging is released to a third-party media, the sender gives up control of how the message will be treated/communicated, if at all. However, if the treatment is positive (and usually it is), this third-party (independent) reporting and potential endorsement is usually more effective than advertising.

Marketing is the practice of the four P’s – creating a product or service that meets a want or need and then pricing, placing, and promoting that product or service. Public relations can fall under promotion. However, public relations also can be used to identify product/service improvements, new products/services, pricing strategies, re-branding, etc. For this reason, public relations can and should be practice in tandem with marketing.

Advertising is the practice of controlled creation and placement of a message (text, audio, visual) via a variety of communications channels/tools. Advertising falls under the discipline of marketing (promotion). Sometimes, though, a public relations message is delivered via ad space in the form of a public service announcement (PSA), a paid ad, or an “advertorial.” Public relations feedback often can identify the proper messaging used in advertising.

Communication planning, rooted in research, is the best way to determine the best mix of these three disciplines.