1. A computer program product comprising computer-readable media having stored thereon, computer-executable instructions, which, when executed cause a computing device to carry out a process, the process comprising: receiving a content request including a first set of attribute values; using at least one of the attribute values from the first set of attribute values to determine a second set of attribute values; traversing a hierarchy of decision nodes, wherein each decision node implements business logic based on one of the attribute values from the first set of attribute values or the second set of attribute values; and yielding a decision from a last node in the hierarchy, wherein the decision dictates how to respond to the content request.