Doesn't Yelp offer astro-turfing for $$$? I hope that this practice doesn't fall under the umbrella of "don't be evil."
http://www.eastbayexpress.com/eastbay/yelp-and-the-business-...
It's not lying -- the good reviews that remain come from real people -- but it's certainly misleading.
For me the first, "that sounds kinda evil" moment was the compliance with gov't censorship (and possibly private data sharing) in countries with poor human rights records. As someone stated, MS (and Yahoo) do the same, but it's still kind of sad.
On the other hand, the value of being able to use Google, despite its marginal risk, seems quite a good "exchange" for many people (that is, the usefulness of say search being weighed off against getting rounded up in say a war on child porn). I think there is a value judgement that is much more nuanced than what you are suggesting.
For a more quantifiable ranking of countries, see:
This seems like they paid people to write reviews, but I see no suggestion that they instructed paid reviewers to be biased. More content is better for everyone, as far as I can tell.
Another Register article (http://www.theregister.co.uk/2009/02/19/yelp_pitch_revisited...) seems to be at most an accusation of unethical ad sales tactics, and it includes the CEO flat-out denying that they'd ever manipulated reviews for money.