Without SEO the likelihood of potential customers finding your website is virtually none. Simply put SEO is the behind the scenes process that allows your site to show up on the first page of Google, Yahoo, and Bing. This free traffic known as organic rankings is what drives business in the world today.
Traffic in the real Google search engine far surpasses anything the old Yellow Page books used to do for business. The problem for you is Google rankings are made up of complex mathmatical algorithms. These algorithms take into consideration a websites on page and off page factors. Everything from the title of your page to the power of the sites linking to yours. All of this determines what keywords you rank for if any. And just to keep things fair Google throws out updates with names like Penguin and Panda. Staying on top of this world is just too much for the average business owner.