Facebook retargeting can be used in a number of ways and is based on your advertising goals, or objectives. There are four main goals in retargeting ads: build awareness, reminder advertising, close a sale, and invite repeat business. When retargeting is used in conjunction with your advertising goals, ads become very effective and drive your return on investment up.
Here's an example of a boosted post from Bustle, who promoted one of its articles on Facebook. Paying to "boost" a post you already posted organically to your Facebook Business Page can greatly benefit content that has mass appeal -- versus a post that targets a specific segment of your audience. Bustle's choice of boosted post here falls into that first category. Facebook Pixel Custom Event Tracking with GTM | Part 2
So what’s the best way to do it? Offer them the opportunity to subscribe to your email list through the Facebook lead ads. These ads let people fill out a form and subscribe to your email list so you can keep in touch with them there and the best part is that they don’t even have to leave Facebook to sign up – they can subscribe right from their newsfeed.