They receive something of value - the promise not to violate the terms of the license. "But wait!" you say. "That seems circular!" Indeed. The issue comes from

They receive something of value - the promise not to violate the terms of the license. "But wait!" you say. "That seems circular!" Indeed. The issue comes from a slight ambiguity in the term "license." The word is used both to mean the contract between Apple and the licensee, and the permission granted in that license. Strictly speaking, the former is a "license agreement," but referring to the agreement just as the "license" is commonplace. Indeed, the first line of the iOS Software License Agreement reads: "PLEASE READ THIS SOFTWARE LICENSE AGREEMENT (“LICENSE”) CAREFULLY BEFORE USING YOUR iOS DEVICE" Apple gives you permission to use (and, to some extent, copy) iOS. In return, you give Apple a promise to use the software in accordance with the terms of the license. You also give Apple other consideration, such as a waiver of liability in the event that you view indecent or offensive material on your iOS device. Your point is an astute one. Section 73 of the Restatement (Second) of Contracts reads: "Performance of a legal duty owed to a promisor which is neither doubtful nor the subject of honest dispute is not consideration; but a similar performance is consideration if it differs from what was required by the duty in a way which reflects more than a pretense of bargain." However, there are other things you give up, as noted above. Additionally, in all practical reality, courts are generally loathe to invalidate a license agreement or any other contract for insufficient consideration.