Keywords in Headers
Placing keywords in H1 (and to a lesser degree H2 and H3 tags) is an effective way to increase rankings. All search engines respond to this on-page strategy although the effect is more pronounced in Yahoo given their greater focus on on-page factors. Make sure the indexing spiders are finding your keywords in your headers, but also that they make sense to your human page visitors. Don't repeat them in abnormal ways just to increase keyword density. Bear in mind there's no magic keyword density percentage that applies to every page or every keyword. As already mentioned, formulas like this vary constantly. What matters most is that your keywords are found in your headers—and don't stress over the number of times you repeat them. Ranking-wise, we know that H1 tags are the most effective. But, they'll probably make your headers look too big. That's where the use of Cascading Style Sheets (CSS) to modify the size of text found within H1 tags are safe and effective. CSS gives you the best of both worlds—a header tag that Google likes as well as a font size that tastefully appeals to people. The best approach is to use a single H1 tag featuring your primary keywords near the top of your page, then have a keyword-rich H2 subheading for each paragraph or section of paragraphs on your page. Not only does this reinforce your keywords in the eyes of the search engines, but it makes it easier for people to quickly scan your pages and pick out the main ideas while reading.
