Yep. There are legal ramifications to shilling products on internet forums, and while I won't name anyone specifically - I AM NOT SAYING ANYTHING SPECIFIC NOR AM I NAMING ANYONE - There was a recent case in Virginia regarding this. The court demanded that the firm in question, which had shills badmouth a competitor, to disclose their identities.
Need I remind everyone that this is a US based website. US laws apply to this website. There are serious legal ramifications to this in the works right NOW in courts NOW regarding "shilling" on internet forums. I saw the links to this court case last week, can anyone link it? In addition to this, Samsung was recently fined millions of dollars in China for doing the same thing. Badmouthing competing products through viral marketing without disclosing the affiliation. I will find this link again in a bit.
In summary:
Legal ramifications
Against FCC rules
This is a US based website.
Not to mention. Let's say I worked for "Ford" and pitched their products while bad mouthing Chevrolet. Doing that on a Ford forum without disclosing my affiliation and the fact that i'm paid to do such is a disgusting practice. That's aside from the LEGAL ramifications.