Abstract: Techniques for modifying a user interface in which respective elements are presented if the criteria for those elements are satisfied include receiving criteria and element characteristics for a new or modified user interface element. The criteria for the new or modified element are compared to criteria for existing elements to determine other elements that could be presented contemporaneously if a request satisfying multiple sets of criteria is received. For each element with corresponding criteria, the characteristics of the element are compared to those of the new or modified user interface element to determine whether the sets of characteristics are mutually exclusive. If the characteristics are mutually exclusive, a conflict exists and information regarding the author of the existing element and the goal or rationale associated with the element may be provided to the user attempting to modify the user interface.

Abstract: Described are techniques for enabling webpages to be generated and customized based on rules created by a user. A user accessing a user interface may select a set of webpage features, the dimensions or other characteristics of the features, and a corresponding set of rule conditions, such as characteristics of a user device, user account, connection, or webpage. When a request to access a webpage is received, an existing body of rules is queried, and the particular rule that is satisfied by the request is determined. A webpage that includes the corresponding features and feature characteristics of the satisfied rule is generated and provided to the requesting device.