Check out the average CPC for some top industries. These are the costs of one click. Mind you, that’s a click that is not guaranteed to convert a customer. With paid campaigns, you have to keep optimizing and testing the ad creative to lower your CPC and increase your CTR. You can imagine that it takes a massive budget to even set a paid campaign in motion. And it requires just as much to keep maintaining it.
A good example is Facebook Custom Audiences. Within this Facebook supports email targeting, the ability to upload customer email addresses and then target those users on Facebook with tailored ads. This lets you micro-segment based on your existing customer database. One application is customer loyalty marketing, promoting offers to existing high value users via Facebook ads.