Shopping carts aren't just for purchasing
Shopping Cart Abandonment: Why You Need More of It points out that online cart abandonment rates will always be higher than the 2-3% in physical retail stores.
According to a white paper by Fry Multimedia, "Most (online shoppers) appear to use the cart to mark products of interest, like turning down or marking a page in a catalog. Items in shopping carts on Web sites represent shoppers' desire to purchase, not necessarily their intent."
Because of this, it's unlikely that online abandonment rates will ever be comparable to traditional ones. Users have a hard time finding what they want on the Internet; shopping carts provide an easy way to bookmark things that they are interested in.
Abandoned shopping carts aren't just shopping carts. They also are important sources of customer information. How important? Imagine what it would cost to put together a list of what each of your online customers was interested in buying!