A List Apart: Articles: High Accessibility Is Effective Search Engine Optimization: "Many web designers view search-engine optimization (SEO) as a "dirty trick," and with good reason: search engine optimizers often pollute search engine results with spam, making it harder to find relevant information when searching. But in fact, there is more than one type of search-engine optimization. In common usage, "black-hat" SEO seeks to achieve high rankings in search engines by any means possible, whereas "white-hat" SEO seeks to code web pages in a way that is friendly to search engines."

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