Why run around to Multiple Traffic Exchanges when you can get SEO, Ads, Widgets, and a few customers with minimal cost.
Most people think that if they build the site, the traffic will just magically pop-up from various search engines through free serp's. (search engine results page) Which is totally not the case. Search engines just like most websites are in constant transition, updating, deleting, modifying or upgrading. This is called web 2.0, while some sites just say that they are in Beta. So, if you are not submitting your site to there engine every single month like a good website owner should be doing your sites links are going find themselves way in the back, behind all the newer stuff that gets submitted properly.