An offer is a promise to do or not to do something that is capable of being accepted by another person. Sometimes Congress enacts laws that unknowingly intervene in written contracts and concluded before the adoption. This can lead to disappointment among the contracting parties, especially if the legislation is not in their favour. Some parties actually sued the United States – and won. The parties in this type of business have opted for billions of dollars. Although rarely, this dispute occurs – but it could be totally avoided with a footnote in the legislation that states that it only applies to contracts written after the effective date. If the undertaking contained in the contract cannot be applied by a court, it is usually because the contract does not contain the necessary elements, making it an unenforceable promise or a non-binding contract. But they are not negotiated between developers and users. They exist only and users must accept them or never have access to a website or app. The result is challenges in traditional contract law. Fortunately, the courts have provided guidance for these agreements to remain applicable. The main element is the indication – that users can find the agreements and have the ability to check them.