The party’s over for many a freebie-addicted blogger as the Federal Trade Commission plans to include blogs under its consumer-oversight aegis:

Mandatory disclosures could change how reviews are perceived online because many Internet users might never imagine that bloggers get compensation.

“I don’t think, for the average reader of a blog, it immediately comes to mind that they actually have a relationship with the company,” said Sam Bayard, a fellow at Harvard’s Berkman Center for Internet & Society. “You think about (blogs) as personal, informal, off the cuff and coming from the heart — unfiltered, uncensored and unplanned.”

This is the heart of it. You can spin the practices any number of ways, from firms encouraging “sponsored conversations” to the formalization of “word of mouth” marketing, but it all boils down to the same dynamic, to wit:

Readers perceive blogs to be first-person journals, and thus assign a certain level of personal trust to them that they withhold from recognizable commercial messaging. Advertisers covet the opportunity to penetrate this trust field with their sales pitches, because they feel the message will be more effective coming from this more-intimate voice.

There are plenty of caveats: A blog is really a format more than a medium, corporate and media blogs aren’t necessary regarded the same way as personal journals, certain campaigns work better than others via this method, etc. But basically, marketing via third-party bloggers involves co-opting a less-formal media channel and disguising the formal commercial arrangement from the audience.

There’s a lot of hemming and hawing about just how the FTC is going to implement its proposed enforcement over a blogosphere of billions. Obviously, it’s only got to worry about the U.S.-based bloggers, and even then, will rely on direct consumer complaints versus specific sites. Ultimately, it won’t bother to probe obvious splogs and hole-in-the-wall blogspot outlets; the blogs with recognizable traffic and reach will be the ones to watch.

I view this development with full acknowledgment that I’ve dipped my toe into this product-shilling. I’ve never been offered three thousand bucks for a glowing post, but I’ve agreed to free footballs and energy drinks, among other trinkets. I’ve always disclosed the arrangement with the advertiser, both because it was always stipulated and because I wouldn’t do it otherwise even if asked.

But in a sense, each individual post on this blog, or any other (for that matter) exists in a vacuum — an explicit disclaimer on a “bought” page doesn’t cover another page where some commercial product may be featured, even in a less-than-flattering light. In some ways, any mention is suspect, because of the precedent established by PayPerPost and other blatant content-hijackers. When the field’s already not level, an overarching policing agency — even if it is the FTC — will help to reset the table, with an assumption of transparency.