"We don't 'monetize' the information you store on your iPhone or in iCloud. And we don't read your email or your messages to get information to market to you. Our software and services are designed to make our devices better. Plain and simple," the letter said.
"A few years ago, users of internet services began to realize that when an online service is free, you're not the customer. You're the product. But at Apple, we believe a great customer experience shouldn't come at the expense of your privacy."
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Apple's rivals, including Facebook and Google, offer a free service to users but have been criticized in the past for their privacy policies. Facebook uses the information it has on its users in connection with the advertisers that purchase ads on the site. Its new messenger app has left some customers disgruntled with permission that says Facebook can edit, receive, read and send SMS messages. Google, meanwhile, uses its information to offer tailored content – like more relevant search results and ads - and has been in a long running battle with a French regulator over its privacy policies.