The first is when you talk about yourself. Directly to people who care to hear you out.
The second is when you pay someone to carry your message. Media for hire, we call it advertising.
The third is when you cajole the 'editorial' side to talk about you, with authority. Publicity is often worth more than advertising, but it's pesky in that it doesn't perform on demand.
The fourth, the fourth is all the rage right now. That's when unanointed kings of tiny media, when bloggers and tweeters and others talk about you.
Why do we persist in believing that these four have much in common? They don't. Being confused about how to classify them is expensive, or worse.
You know you're in trouble if someone on your team says anything like, "But how do we do this quickly? And at scale? Is there a way interns can churn through names? We have money to spend, hurry!"
There are some that would be delighted if PR and social media would just own up and start playing by the rules of advertising. In other words, you ought to be able to buy this sort of buzz. It's more efficient, more convenient and more predictable.
Of course, it doesn't work that way. Buying your way into the fourth horseman doesn't work. Professionalizing it doesn't work so well either. What works is making something worth talking about.
As it should be.
If you're hoping that this now important form of media is going to sit there and promote your average stuff for average people made in bulk but pretty cheap product merely because you're used to paying media companies to run ads… I think you're wasting a lot of time and money.
This goes deeper than that. You'll need to take that money and change the product and the service instead.