What is the best way to handle a user that appears to be a shill for a company? My community is based around cars and it frequently has a user appear in conversations saying how "X company is awesome because of Y". It's not spam, because they aren't posting links products. It's not really trolling because they aren't attacking anyone. But, if anyone even mentions company X, this user will be there within hours explaining why Company X king of the world, often with some news article or press release backing them up.
How should this type of user be handled from the perspective of a community member? The administration doesn't seem to mind that much - at least publicly.