Drive More Traffic by Link Building

Link Building Services - How effective? Just a short note about various link building services available. I did review these websites which are selling one way links to help your business website rank better on search engines. They claim to get you more visibility on search engines and drive more traffic to your website using "organic search results". Now the question that comes to my mind is, if they can do this for you, why dont they help their own businesses first? They are advertising on web design blogs and forums and anywhere they can find a place to advertise their link ...