Merchants can reach shoppers who have visited their sites or mobile apps.

Facebook Inc. is giving retailers and other marketers a new way to reach consumers who visit their web sites or mobile apps but leave before completing a purchase.

The added functionality is part of an update to the social network’s Custom Audience targeting tool. Custom Audience lets Facebook advertisers target shoppers based on non-Facebook information they’ve collected, such as shoppers’ e-mail addresses, phone numbers and, among game and application developers, their user names. The advertiser need not share any personally identifiable data with Facebook.

The new feature enables an online-only bike retailer, for example, to reach a consumer who shared his e-mail address with the site to use its design-your-own bike tool but didn’t make a purchase. Using Custom Audience, the retailer can display to that shopper a desktop news feed ad that encourages him to finish customizing the bike online. Or a fashion retailer that has a mobile app can deliver ads encouraging consumers who have downloaded its app but haven’t used it in a while to use it to find new deals.

Here’s how Custom Audience tool works: the retailer uploads its customer information, such as an e-mail list, using Facebook’s ad management tool. The retailer scrambles that information, creating what cryptographers call a “hash” that can’t be decoded to recreate the individual addresses; Facebook does the same with its users’ information. Facebook then matches up the retailer’s hashes with its hashed user accounts. The retailer can target that matched group with any of the social network’s ad formats. It can also focus on particular segments, like male consumers in Chicago who are between 20 and 40 years old.

The new Custom Audience functionality is the social network’s second tool that lets retailers and other advertisers retarget shoppers. However, unlike with the other retargeting tool, the ad-bidding network Facebook Exchange (FBX), which requires marketers to work with vendors to bid on ads, marketers can craft their own Custom Audience retargeting campaigns.


“We anticipate that marketers will use FBX and web site and mobile app custom audiences in different ways,” Facebook wrote in a blog post announcing the new feature. “For advertisers who have a large number of products and advertise to multiple audiences, FBX is the better solution. For businesses that don’t typically work with third parties, Custom Audience will allow them to show ads to people who have been to their site or mobile app and still utilize Facebook’s targeting abilities.”