Cost of coverage
Advertising refers to the paid publicity of your business and your products/services. You pay an advertising medium to spread word about you. As against this, public relations are completely free – it refers to the reports in the media about you. This can be achieved through press conferences and by sending press releases to media houses.
Since you pay for advertising space, the duration of an advertisement can be controlled by you. You can determine how long an advertisement will play on a particular medium, if your budget allows for it. On the other hand, the shelf life of public relations is shorter. It is controlled by the media house, and it is they who decide whether to publish/broadcast a report about you or not. Even if they do decide to feature you in a news report, it will be only once as against the possibility of advertising repeatedly.
You can have control over the time duration of your advertisement, its content, the visuals used in it – everything, since you are paying for it. On the other hand, since public relations are free, you do not have creative control over the content. The light in which you are represented in a news report is up to the concerned media house.
To develop a successful advertisement, you need to be creative enough to come up with a message, visuals and music that will appeal to the society at large. You need to be able to attract people with your advertisement, and convince them to buy your products/services. For successful public relations, though, you need to have a nose for what will make for good news. You need to focus on building good relationships with media houses, and on pointing out news-worthy developments around your business to them.
Impact on prospective customers
Customers understand advertising as a form of publicity that you have paid for, and have control over. They are more likely to believe a third-party report about your business and your products/services – i.e. public relations – as it is largely considered to be unbiased, unpaid and uncontrolled by you.
Corporate social responsibility
If you undertake a special event as a part of your corporate social responsibility, it might be considered imprudent of you to take out an advertisement about it. However, in case of such special events, it would be a great idea to send a press release to local media houses or hold a press conference. The media might decide to cover the event, which would create a very good impression about you.
In an advertisement, you use action-oriented, attention-grabbing buzzwords, with the intention of convincing prospective customers to buy your products/services. The style of communication used in a press release or a press conference is totally different – in this case, it would be very formal, matter-of-fact and more in the form of news than a commercial activity.
In advertising, your focus in on your target audience, using a medium that is popular with them, and using content that will grab their attention. However, in case of public relations, you need to get the attention of the editors of media houses and reporters with a news-worthy angle.