Posting ads on free online classified advertising websites is an often overlooked, but powerful way to increase traffic to your website, and increase the number of high page rank backlinks to your site, which is good for your site's SEO. Classified ad sites are perfect for marketing your products and services because visitors frequent these sites when they are looking to purchase something. If you write a compelling ad, include a good picture and a keyword rich description, if your ad is placed in the appropriate category you should get lots of clicks and traffic from it.