On Monday Sridhar Ramaswamy, Google’s Senior VP of Ads and Commerce, announced a new advertising program which will allow advertisers to target online campaigns to their existing customers. The program, called Customer Match, will allow companies to upload existing lists of their customers’ email addresses and cross-reference them with their existing Google accounts to offer customized advertising content across Google Search, Gmail, and YouTube. “Let's say you’re a travel brand. You can now reach people who have joined your rewards program as they plan their next trip,” he wrote in the post. A complementary program, called Similar Audiences, will allow those advertisers to go beyond remarketing, targeting potential new customers based on the information from their existing customer base. 

Allowing brands to target their existing customers is already practiced by companies like Twitter and Facebook. Unlike the two social network giants, Google plans to limit the amount of information accessible to advertisers through the Customer Match program. Advertising Age reports that “All three products let brands target people based on their email addresses. However Facebook's also includes people's phone numbers, user IDs and mobile ad IDs, and Twitter's includes people's Twitter account handles.” Furthermore, Google offers its advertising partners the option to protect personally identifiable information, including the email addresses themselves, by providing the information to Google in a hashed (unintelligible) format. 

The rollout of these new advertising services by Google comes at a time when ad-blocking software is becoming more prevalent and threatens to negatively impact online advertising revenue. Perhaps by offering a greater level of remarketing and targeting, the search giant hopes to offset any potential losses. While there are always privacy concerns, Google’s remarketing program provides less information to advertisers than Facebook and Twitter. Users can opt out of the Customer Match program’s targeted ads by opting out of personalized ads or by muting individual advertisers through their Google Ads Settings.