First thing you need to understand about search engines
Search engine have done all the hard work of collecting and analyzing web pages, BUT it only makes that information available when someone does a search by entering words in the search box and hitting return. The words people use when they search therefore determine the results the search engine presents. We call them keywords: keywords are only the words people use when they search.
Use keywords in your website copy and you will prosper: ignore them and your online business will surely fail.