It had to happen. With the dramatic rise in the popularity and number of blogs and other social marketing sites on the web, sooner or later merchandisers would get wise to the fact that they can use them to pitch their products and services. And for just pennies on the promotional dollar.

How? By offering free merchandise or cash payments to bloggers who will then be favorably disposed to write positive reviews about new products. And with blog postings being indexed by search engines in just a few days or even a few hours, it’s an incredibly cheap way to gain positive exposure for their products and brands in cyberspace.

… Not to mention that many readers will not be wise to the authors’ tidy mercantile relationships with the companies whose products they are reviewing. This despite the efforts the Federal Trade Commission is making to update its nearly 30-year-old advertising guidelines to cover the new new-fangled techniques brought forth by the cyber revolution — tactics few could even have dreamed of just a few years ago.

How long will it be before the FTC has these new guidelines in place? Who knows? For the moment, there are no hard-and-fast rules regarding paid reviews. But there are some moves being made within the industry to provide “full disclosure” to readers. Blog entrepreneur Ted Murphy of IZEA Social Media Marketing requires his “for-hire” bloggers to insert an icon next to each product review that states: “Sponsored Post. 100% Real Opinion.”

“One hundred percent real opinion?” Does anyone seriously believe any sponsored post will be completely free of bias?

Of course, sponsored bloggers could write a negative review … and then watch as it’s the last time they ever have the opportunity to write for that supplier. Practically speaking, that’s not going to happen — and everyone knows it.

A more fundamental concern is what paid pitching is doing to the credibility of the blogosphere in general. If people find out that even one or two product reviews they read turn out to be nothing more than disguised advertising for the merchandiser, it could cripple the credibility of bloggers overall in the minds of those readers.

This whole phenomenon has the risk of turning a highly powerful consumer information resource into a caricature of itself. Those who read product reviews tend to be the more cautious – or the more suspicious – consumers among us. And so, despite providing every assurance that bloggers who are paid cash compensation or receive merchandise freebies for their posts will remain honest in their opinion … that’s not how it’s going to be received by the audience.

Advice to bloggers: If you value your credibility and your reputation, don’t accept quid pro quo compensation from companies whose products you are reviewing. Advice to consumers: As always … be careful of what you read online.

UPDATE: Two years later … and not much has changed. Here’s Honda’s latest shenanigans.