• by Mark Walsh  @markfwal, February 5, 2013

Facebook has added a new feature to its custom audience ad service that allows marketers to target an audience segment with a similar customer profile to one previously uploaded they.

Launched in September, Custom Audiences lets marketers retarget their existing customers and prospects on Facebook by uploading a list of their email addresses and/or phone numbers. During the company’s fourth-quarter conference call last week, Facebook executives spoke of promising early results for the ad offering.

Through the new Lookalike Audiences feature, “advertisers can expand their reach to specific geographic areas or audiences who are not already fans of the company’s page while still maintaining the desired demographic profile of their existing audience using Facebook’s algorithms,” the company said Tuesday in a release.

Lookalike Audiences is currently in beta in Facebook’s Power Editor tool for managing large or multiple campaigns.