You can read Grady's reviews on Amazon Canada here, and Amazon UK here, and I even found his reviews on Amazon.de. Soooo, what's so different between the reviews on those sites and his reviews on Amazon US? Yes there are fewer reviews, but where is the TNGHVM? If, as the most prevelant theory is that GH has multiple Amazon accounts and uses those to vote himself silly, wouldn't he be doing it on those sites as well? He'd be #1 in a heartbeat without Harriet to contend with. If he's vote mad as we all believe he is, why aren't the votes there as well?
I suspect that it's not multiple accounts, but that GH has found some software and/or is able to manipulate the Amazon votes and that's where the massive votes come from, and if he could do so on the other sites he would as well. Besides, try getting an extra Amazon account and give yourself a vote or two. You have to log in, find the item post the vote, log out, log in again on new identity, vote again, etc. Even with the fastest connection and fingers of fire no one could do that in the time frames we've seen those votes come in.