Why are abandoned shopping carts bad for e-commerce businesses?

Every abandoned cart adds to the lost revenue. The cost of cart abandonment is estimated at $18 billion for abandoned carts online retailers each year.

Think about the profit you were going to make with the successful order placement. However, the customer just abandoned that filled cart, and you lost your margin then and there. The customers of these abandoned carts are hot leads or potential buyers that gave up on your business, so that's a loss of one highly convertible customer as well.