16. The non-transitory tangible computer-readable storage medium of claim 15 , wherein the prediction model is configured to: monitor the engagement levels of the previous social media messages, and adjust the weight values of the one or more common message information attributes identified by the prediction model.
15. The non-transitory tangible computer-readable storage medium of claim 14 , wherein the server determines the predicted engagement score by: identifying, based on previous social media messages and monitored engagement levels of the previous social media messages, one or more common message information attributes having a predicted impact on engagement, each common message information attribute having a weight value assigned by the prediction model corresponding to the respective predicted impact; and calculating the predicted engagement score based on a measure of the one or more common message information attributes in the message information of the social media message being composed.