Forbes has gotten lots of attention for its new editorial plan: with True/ Slant's Lewis Dvorkin in charge, Forbes is flooding its site with blogs from both staffers and outsiders. And, it turns out, from advertisers. Ripoff—for the advertisers.

Ad Age today reports on Dvorkin's plan to integrate blogs written by advertisers into Forbes' own editorial mix, so that a blog from an auto company might stand alongside blogs from Forbes beat writers, and from whichever outsiders agreed to have their own blogs hosted on Forbes' site. Says a Forbes exec: "If an auto manufacturer is in the midst of a new-car launch and has a great story behind the creation of a high-performing engine, they should be able to tell it and to stream into our tech topic flow, or automotive topic flow, as long as it's clearly labeled."

The immediate debate over this approach will be about whether it goes too far towards destroying the wall between editorial and advertising. But the more interesting debate would be: is a blog like this even worth paying for, for an advertiser? Forbes seems to be pioneering a sort of quanity-based approach to online editorial content, figuring that if they can get enough blogs by enough writers with enough content up on their site, traffic and influence is sure to follow. That's a dicey bet from an editorial standpoint, but from an advertising standpoint, it seems like a downright waste of money.

Online content is infinitely replicable. Buying a blog on Forbes' website is not like buying a page of advertising in a print magazine. A magazine has a finite number of pages; a page of advertising is a measurable claim on the content of that magazine, and therefore on its readers. But online, it takes nothing for a site to start up and host dozens or hundreds of new blogs; whether people read them is another matter. Plenty of magazines and newspapers tried wildly adding bunches of blogs to their websites, only to find that they have a hard time drawing attention. The web works differently than print; online, content is much easier to ignore than it is in a magazine.

As are ads. So presuming that readers will go out of their way to read a corporate-written blog simply because it appears on Forbes' site—well, it's optimistic, at least. Good luck to those advertisers. You better hire some really, really interesting writers. You'll need them.