You have a handle on what modern SEO content should be, but it's also vital to understand what it shouldn't be. Nielsen's research described what kept readers on web sites and shed light on what drove them away. Search engines take these same factors into account and rank pages down or even remove them from ranking altogether.

Duplicate content can sink a site. Even legally obtained duplicate content such as articles linked whole from news feeds and large blocks of attributed quotes diminish a site's SEO value. Readers have no reason to visit a site that gives them other sites' news verbatim. Page ranks will decline over time without original content.

While you don't want large blocks of duplicate content on your site, you want the timely information that your news feeds deliver. Build fresh new content on the foundation of other information whenever possible. It takes more effort to assimilate and summarize a news story or to use it as a link within an original article, but doing so will cast your site in a more positive light. If you add sufficient value with sharp writing and relevant links, you'll find yourself in the search engine stratosphere.

The old method of following keyword formulas and meeting keyword percentages is not only outdated, it will actively lower your site's rank. Heavy keyword-loading is the hallmark of advertising web sites, and search engines know it. Using related words and relevant phrases to enhance topic recognition marks your site as valuable and drives its search engine value higher. Varied writing is also more readable to your human visitors.

Nielsen found that human readers shunned sites full of filler phrases. Clear, concise web writing has greater value than sprawling pages full of fluff. Hyperbole and promotional language -- describing a product as "the best ever" or "the perfect solution," for example -- contributes nothing to the meaning of the text. Human readers filter out fluff and software ranks down sites with too much of it, so eliminate it from your site.

Search engines change their algorithms regularly in an effort to provide their users with more relevant results. The state of SEO art changes with them. The only constant in web writing is its human audience. Pages that provide novel, appealing content in a reader-friendly format will rise to the top of the rankings.