Abstract: A platform enables a business to learn about a user based on characteristics of the user and without knowing the identity of the user. The business specifies characteristics of users of interest to the business. When a platform user begins a session, a process representing the platform user interacts with the business's specification so that the business obtains the characteristics of the user without knowing the identity of the user. If the user's characteristics match the business's specification, then the platform takes an action specified by the business, such as sending an offer or advertisement to the user.