“You can’t buy that.”
It’s the phrase every PR pro SHOULD dream about.
The front page, above the fold, favourable-to-you editorial piece: You can’t buy that.
The Flip cam video one of your company’s fans made while having fun with your product that goes viral : You can’t buy that.
The firestorm on Twitter that came about because you built a better mousetrap: You can’t buy that either.
Any PR person who tells you these outcomes are 100% controllable/creatable is a liar. Don’t hire them. It’s what they should be shooting for though.
Ask the PR person/people/department/agency about what they plan on doing to create conditions for these sorts of things to happen. They should have a well thought out answer.