REAL-TIME ADAPTIVE PROBABILISTIC SELECTION OF MESSAGES

A facility selects a unit of content to include in an instance of a content container. For each of a plurality of units of content, across a plurality of other instances of the content container distributed during a foregoing period of time that included the unit of content, the facility determines both an average level of success achieved by including the unit of content, and a measure of the level of variability of the level of success achieved by including the unit of content. The facility scores each unit of content by selecting a value from a probability distribution that is based on the determined average level of success and measure of the level of variability of the level of success. The facility selects one of the units of content to include in the instance of the content container based on the determined scores.