LTV, or lifetime value, in Facebook ads, refers to the total revenue that a customer generates for a business over their entire relationship with that business. In the context of Facebook ads, LTV can be used to measure the effectiveness of a Facebook ad campaign by looking at the revenue generated by customers acquired through the campaign.

By understanding the LTV of customers acquired through Facebook ads, businesses can make informed decisions about how much to spend on Facebook ads, and how to optimize their ad campaigns for maximum ROI. For example, if a business knows that the average LTV of a customer acquired through Facebook ads is $100, it can make decisions about how much to spend on ad targeting, ad format, and ad placement, based on the expected return on investment.