What best determines whether a borrower’s investment on an adjustable rate loan goes up or down?

There's a cartoon that has become a social media meme. two pigs are chatting. the first pig says, "isn't it great? we have to pay nothing for the barn." the second pig replies. "yeah! and even the food is free." this cartoon is frequently linked to a quote that goes something like this: "if you're not paying for it, you're not the customer; you're the product being sold." what do these statements imply about social media? what are the specific ways that social media users become a product that is being sold?