In a recent article on Business Insider, Jillian D'Onfro (@jillianiles) discusses how Facebook is rolling out shopping on its platform:

"It's letting certain stores sell their products directly through the social network via a "buy" button on their Pages."

This features will be rolled out slowly, as the last time Facebook tried a "buy" button in 2011, the experiment bombed.

Our guess is that many of the brands experimenting with this feature will have a strong advertising foothold on Facebook. 

Why? Facebook's organic reach continues to fall. According to Forbes, as of May 2015, Facebook's organic reach was measured at less than 6.5%. With little organic traffic, the only way to get a return on investment (ROI) out of a "buy" button is with Facebook ads.

If you are a marketplace entrepreneur, you should be watching Facebook closely. Sprecifically, you should be looking into whether or not Facebook advertisting would be a good way to send targeted traffic to your marketplace.