I contacted AEG for a response to the claims, and was given the following statement:

It has been brought to our attention that there is some confusion regarding AEG's relationship with NVIDIA Corporation; specifically that AEG has been retained by NVIDIA for "hiring employees to shill for clients on online discussion forums," as recently stated by The Consumerist.

While there are agencies that engage in the practice of paying consumers for their opinions, it is not-and never has been-a practice of the Arbuthnot Entertainment Group. We do work to solicit the opinions of the community for NVIDIA. The names of those individuals whom we solicit opinions from are not made public in order to assure the quality and honesty of feedback from consumers. Furthermore, we take this precaution so that they, the enthusiast, are not barraged by individuals inquiring about participating.

AEG has found that monitoring forums and reporting to NVIDIA problems, bugs or fixes mentioned by members of the online community is a far more honest and effective way for NVIDIA to be aware of the needs of its customers. It is not our goal to direct public opinion; we monitor discussion in the community as a way to seek feedback from consumers, be it positive or negative, so NVIDIA can improve its current and future products. It is the ongoing opinions of the hardware community that direct the hardware vendors, not the other way around.

The practices AEG refers to in this statement--monitoring forums and observing customer response to products as well as contact individual community members for feedback--could very well have been be misconstrued as directly advocating the products, especially since The Consumerist never seemed to get a straight confirmation, either from the accusers or from Nvidia, that shilling was specifically what was going on. For the record, Shacknews has been solicited to participate in "shill" programs in the past, and is also on AEG's press list for various products, but AEG has never been one of the companies doing such soliciting in our case.

Given the anonymous nature of the internet, it is obviously difficult to conclusively prove one way or the other whether AEG has been involved in these practices. However, the suspicion of The Consumerist was largely driven by a lack of a clear response, which AEG provided to us today, and the initial "evidence" pointing to AEG's practices was entirely based on statements from AEG's website (explained in the quoted response above) rather than specific forum activity. From there, I suppose you'll have to draw your own conclusions.