Facebook appears to be preparing an option for advertisers to target users by email address, user ID or phone number, based on an option that was temporarily visible in the Power Editor tool.
With a select group of premium advertiser, Facebook is targeting audiences by email address, UID and phone number options. These are powerful new opportunities for businesses to reach their existing customers and leads, who may be increasingly difficult to reach through traditional email and telemarketing campaigns. If this test rolls out to all Power Editor users and the Ads API, companies will be able to remarket to people through News Feed and other Facebook ad units.
Some Power Editor users temporarily had access to a new “Custom Audiences” tab today. The tab originally appeared next to the “Page Posts” tab, but soon disappeared. Advertisers can select which type of information they are targeting and then upload a CSV or TXT file with email addresses, user IDs or phone numbers. According to the screenshot above, personally identifying information will be hashed before being uploaded to Facebook, and there are additional terms for using this functionality.