Imagine, you are a kids jacket retailer and have a Shopify store. Yes, these exists and are popular. How do you get users to your store? Yes, you use Facebook. Do you know how you Facebook here? You create a group with VIP members and offer them an exclusive discount over new jackets. This builds loyalty and provides word of mouth marketing. Next you create a page and try to post different images/videos of kids in your exclusive jackets and build followers who will like/share your post and thus get you free organic distribution. Next, you use fb ads and target your specific demographics (say women 25-40 yrs old who are interested in kids) to get users in.
This is a real thing. One of my best friends has a multimillion dollar business a yr on kids jackets and all she uses for marketing is facebook and she swears by it.