Majors search engines such as Google, Yahoo and MSN all have different algorithm formulas, therfore what one does in one search engine may not necessarily translate to the others.  Most businesses  seem to care more about Google  since they get the majority of the searches. Each search engine takes into account the Meta Title,  Meta Description and the content that is visible (not images)  on the site. The meta keywords are not as important as they used to be, but some search engines still take them into account.