But I have friends running ecommerce sites in more competitive niches. They compete with the likes of Amazon, Walmart, and other mass-market retailers that sell everything (albeit rarely covering the niche products as well as the specialists do). For years they have been insistent that, despite what Google's guidelines say, they wouldn't stand a chance of being found in the organic search results if they didn't buy links.
Since Penguin things have gone topsy turvy for them. Many of the competing businesses with good sites and happy customers have disappeared from the rankings after receiving penalties. Some are going bust as the margins are too thin to make adwords work. The spammers with junk sites suffer (good), but also the smaller businesses with good sites offering something extra that can't be found from the big box stores. As a result, the consumers suffer too (as all they see is a small selection of products on Amazon and a smattering of link-buying businesses that have been lucky enough to evade the penalties).
I'm not familiar enough with this situation to offer a strong personal opinion. But I wonder if this might be an issue that Google sweeps under the carpet somewhat... That actually "build it and they will come" doesn't usually work when you're up against companies with thousands of links (many of which are paid links, whether they look like it or not).
