SEO is very important than SEM...SEM (search engine marketing) is a form of marketing a website by promoting a website to increase it's visibility in search engine result pages.This is done through placing advertisements paid or unpaid, listing in directories,ads in banners.SEO means search engine optimization.It is essential for every website.If you want page rank,visitors for your site you can do seo.You can get seo service at
Thewebpole.com SEO submit sites in search engines.But SEM wont do this submission.