Inevitably, aside from a handful of established practitioners, these services tend to proliferate in recessionary times.
Many pay-as-we-plug services are spawned by newly unemployed journalists looking for a quick transition to a related media industry. Setting up as one-man bands, they offer solutions based on knowledge gained from their past professions and a pledge to cut through PR excesses.
Results-only PR flatters to provide obvious and cost-effective answers to simple questions. Why pay for high-sounding PR-speak and all that strategising when all you want is media coverage?
It is a seductive line of reasoning but often fails to provide the solution offered by the sales pitch. I know of many such arrangements that have descended into unseemly rows about how a certain 'name check' came to appear in a certain publication.
Others have ended in tears about derogatory product mentions when the client is presented with an invoice from the results-only practitioners, who appear to believe any mention constitutes good publicity.
Scales of charges can also cause endless ructions with client and promoter falling out over what constitutes a feature and what is 'only' a news story.
I also happen to believe results-only PR, while having a limited useful application, tends to undermine the skills base of the PR industry. The essence of good public relations - of which media placement is a key element - is control and strategy.
Both are based on a trusting long-term relationship between PRO and client. A crucial part of what the client is paying for is the careful and skilled long-term maintenance of strong media relationships.
Results are what good PROs deal in. But they are achieved through the strategic interfacing of client and media, and not through quick fixes.