I have a friend that is a pretty popular blogger, and I asked him today why he had been talking about a certain product so much. He confided in me that he was being paid to be a product evangelist. When I told him that I had never heard him disclose that he was getting paid to evangelize the product he said that his contract had forbid him from disclosing this.
I was floored and the conversation went pretty much downhill, out of respect to him I am not going to mention his name or blog, but I told him in no uncertain terms that I thought it was wrong, and that continuing to promote a product without disclosing that he was getting paid was unethical.
He was not happy with my position, and to add insult to injury he told me how much he was getting paid and that pissed me off even more. The company in question probably needs all the help they can get, but it just pisses me off so much that I called the company in question and asked that my account be canceled. I did not go into why I was canceling but if this is becoming more prevalent and bloggers are not disclosing when they are getting paid to talk about a product then these actions will have negative long term consequences of the short term gains.
I will never ever do a product review or talk about a site without first disclosing the relationship to do otherwise is beyond my comprehension level.