In 2008, Apple filed for and received approval from the U.S. Patent and Trademark Office to trademark the "App Store" name to describe a service that allows its iPhone and iPad customers to purchase and download applications, video games, and other software. Over the past few years, Apple has invested millions in advertising and publicity and customers have purchased millions of dollars of software from its "App Store." However, Amazon.com claims that Apple did not have exclusive rights to the name because other firms used it to describe their online storefronts where consumers can obtain software for smartphones and tablet devices. In March 2011, Apple filed a lawsuit against Amazon for violating its trademark. Why should Apple rigorously protect its "App Store" trademark?