To encourage customers to leave positive reviews on Facebook, businesses can offer a special promo code available on their Facebook pages to be used at checkout. The promo code serves to track what kind of customers are visiting the Facebook page most frequently and to send follow-up e-mails asking customers to leave a review on the page, writes social media marketing specialist Kristina Allen. Consider using paid ads to fuel even more earned media and take full advantage of Facebook as a platform, she adds.