"News Feed Ads", also called "Sponsored Stories", "Boosted Posts", typically exist on social media platforms that offer a steady stream of information updates ("news feed") in regulated formats (i.e. in similar sized small boxes with a uniform style). Those advertisements are intertwined with non-promoted news that the users are reading through. Those advertisements can be of any content, such as promoting a website, a fan page, an app, or a product.
If you’re in the “how to make money online” market, you’ll make more in affiliate programs than Google Adsense or most other advertising programs, simply because of the points Yaro mentioned. Affiliate income is also one of my biggest sources of income. I wrote this short article of affiliate blogging tactics: http://www.easywordpress.com/labs/affiliate-product-blogging-model-explained/