I received some pretty convincing information that at least one big camera manufacturer is using Internet trolls to promote their own products online on several Chinese photography forums and websites (unfortunately I cannot publish the entire email in order to protect my source):
There is currently a major campaign from *** going on in a public Chinese forums. It's done by a *** PR company using Internet trolls to post messages to promote *** products. The PR company has been known to use trolls for its clients for some time.
For now I prefer not to mention the company name, let's just say it's one of the top 3. This may explain some of the comments you see online on photography related websites (including this blog and NikonRumors).
Image credit: Babbletrish (flickr)