We get this question a lot. Although some apps will allow you to award points for likes and shares on social media, this is largely prohibited among social networks. Facebook and Instagram especially do not condone this as it is considered incentivizing actions which the platforms themselves would like to maintain as organic.
This has been the case since 2014.
"You must not incentivize people to use social plugins or to like a Page. This includes offering rewards, or gating apps or app content based on whether or not a person has liked a Page. It remains acceptable to incentivize people to login to your app, checkin at a place or enter a promotion on your app’s Page. To ensure quality connections and help businesses reach the people who matter to them, we want people to like Pages because they want to connect and hear from the business, not because of artificial incentives. We believe this update will benefit people and advertisers alike."
Since this is a largely prohibited behavior, as much as we'd like to offer it, we don't want to put the Glow app or your business's facebook page at risk of getting suspended for violating the network's terms and conditions.
However, all is not lost! We do allow your customers to share their referral link on many social networks from within the Glow widget. Although they don't get points for sharing, they do get points when one of their friends signs up or makes a purchase (its up to you how you reward them!). This still incentivizes them to share your site with friends without putting you at risk of suspension.
For more information, you can check out Facebook's guidelines on proper use of the platform and APIs here.