Terms of Service are rules by which one must agree to abide by in order to use a service.

Certain websites are noted for having carefully designed terms of service, particularly eBay and PayPal which need to maintain a high level of community trust because of transactions involving money. However, to attract new members and maintain current members, the terms must be perceived as fair and must not be needlessly bureaucratic. For the sake of good public relations and effective community building, the organization should strive to form a social contract that balances the organization's interests with a set of rights granted to the membership.