Even though Google's share of search has been drifting lower, the last stats I saw still had them at 2/3 of all US searches. Given that market power, they should definitely be under scrutiny from anti-trust regulators.
Having said that, of course they're going to bias the search results in a way that favors themselves. Search for "Samsung Netbook", towards the top you'll get a link to Google's shopping engine mixed in with the regular links. It's not called out as advertising, it's just one of the first links for that term.
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