One can learn how often a specific phrase is searched for by looking it up with the google keyword tool, that’s made for adwords advertisers who bid on keywords. Site designers striving to rank for ‘niche’ terms that return thousands of search results, rather than impossibly competitive phrases with millions of search results will identify keyword phrases that are searched only a moderate number of times, but still have some commercial value.
Once some specific niche keywords phrases are identified, they are placed in domain names, page titles, header text, body text and image captions, alt text and file name. This repeated but natural looking use of a key phrase makes the page score highly for that key phrase, which helps the page rank for that search term.
with millions of pages matching some search terms, the only realistic way of attaining the dream of appearing on page one of google is to optimize the site for a relatively obscure term that’s popular enough to attract houndreds or thousands of visitors to the big fish in a little pond.