While I think the blog post and its example scenarios are compelling, if "all" that's going on is their automated filter "doing its job", then I might suggest their filter needs more work. It's certainly a tough job it has, and maybe an impossible one for an algorithm to do fairly. It's great that they're trying I guess, but I'm just not sure how reasonably certain they can be of its efficacy. How do they measure it? In the case of someone reviewing their friend's business, how do they know they don't also like the way they do business?
Many people structure their entire business world around relationships, reciprocity, even friendships, and many good, long-time customers become friends of the business owners or at least of employees. How do you fairly judge these reviews? Even in real-life, *knowing* the connections, how do you fairly judge!? If I hear such-and-such restaurant is good but I know that the person I heard it from is friends with the owner, do I think less of the recommendation? Probably, at least a bit. But then maybe I know the person recommending very well and know they'd be unbiased, as they've told me before that another friend's establishment is terrible, even though he's a good friend. Etc, etc, on and on.
So how do they reasonably expect a software algorithm to do this and not make *lots* of mistakes and piss people off? I don't know. But I recognize the difficulty of providing a review site without such filtering as well. My personal approach would be to allow up/down rating of reviews by visitors, maybe a "mod-point" like system as-in Slashdot, and then a "trustworthiness" rating that comes out of that and the algorithm's determinations, and a "trustworythiness threshold" that you could set while browsing reviews, again like Slashdot. Outright removing reviews just seems unfair and error-prone in the extreme. It's no problem if their algorithm weighs heavily in the decision to mod down a review or whatever, but to remove it entirely unless it's obvious spam (e.g. get viagra here!) seems presumptuous.