As more small and medium businesses start promoting their sites and Facebook pages online, self serve advertising has been growing along with them. Now more than ever, there is a great opportunity to market your campaign in a long list of platforms.
While the quality of traffic varies greatly among these, you never know where you may find hidden gems that can return a great ROI. My advice is to proceed with caution and always test with a small budget before taking the full plunge.
This list was compiled from a variety of sources online.