• by Mark Walsh  @markfwal, January 28, 2014

Facebook in October announced it was testing a new capability for its Custom Audiences tool that would allow companies to retarget people who visited Web sites or mobile apps. Previously, businesses could only retarget Facebook users through customer email lists and/or phone numbers. On Tuesday, the social network said it was rolling out the expanded features of Custom Audiences to all advertisers.

As an example, Facebook said a travel site could use Custom Audiences to reach just people who searched for flights but never made a reservation -- and hit them with a newsfeed ad offering 10% off their next flight reservation. Likewise, a mobile retail app could install the Facebook or third-party SDK to retarget people who left items in their shopping cart.

“By placing the Facebook remarketing pixel on their Web site, or the Facebook or third-party SDK in their mobile app, more marketers can now build Custom Audiences based upon the actions people take while visiting their site or mobile app -- and then show deliver ads based on these actions,” stated a post on the Facebook for Business blog.

As for results from initial campaigns, Facebook said Zaggora, a women’s activewear company, had seen three to six times the return on ad spend by retargeting visitors to its Web site. Separately, financial site Seeking Alpha saw its average cost per install fall by 28% when retargeting mobile app install ads to those who previously came to its site.

Facebook indicated that the general rollout of Custom Audience retargeting by Web sites and app traffic was one of the additional steps it will take in the next several weeks geared to direct-response marketers. In that vein, the company also said today that when a marketer creates a Page post ad, they will now have an option to add a call-to-action button.

The button will appear in the lower right-hand corner and advertisers will be able to choose from five actions: Shop Now, Learn More, Sign Up, Book Now, or Download. The new offering underscores Facebook’s heightened efforts to turn developers and small and medium-sized business into paid advertisers on the social network.