Here's a blogger talking about the use of blogs by marketers. I can see how this would be effective. And I firmly believe that we should be free to use our blogs in any way we please. But if this practice were to become widespread, I can see where eventually all blogger's credibility might come into question. Did I link to a certain site because I thought it was of interest, or was I being paid to do so? And since there are no hard and fast rules, how much disclosure am I required to give? What if I truly love a service and blog extensively about it, then later am offered compensation for having done so?
Could this also lead to attacks on blogs that complain about a product or service by paid hackers?