If the content is good and nobody is hiding their affiliation with it then the correct word is just "posting". Otherwise it might fit within one of the categori

If the content is good and nobody is hiding their affiliation with it then the correct word is just "posting". Otherwise it might fit within one of the categories you mentioned. I agree that it would be better if they were up front with their affiliation, but hiding it (astroturfing) is not the same as not divulging.