From Thikipedia
The flip side of this is that all of the above is GREAT practice for seacrh engine optimization (SEO). With SEO, the job is essentially the same: you need to convince Google et al that you're relevant to a seacrh query. With SEO, however, the thing you need to impress is a piece of software (a ‘spider' that crawls your site) rather than a human being. The good news is that they tend to read a web page in much the same way as we do. They'll get to know you through your language and how you use it. So, to encourage Google to categorise you properly, you need to deploy keywords in strategic parts of your pages headers, subheads, links, bold text, footers, etc. There are variations on this theme that will help, but that's pretty much it in a nutshell. (Although if you're interested in the science, then we recommend you read our paper on SEO.)
