Methods and systems for scalable extraction of episode rules using incremental episode tree construction in a multi-application event space comprise compiling events from multiple, different domain logs into in a universal log file, rolling domain-dependent and domain-independent windows through the universal log file to identify distinct event-pattern episodes, adding episodes to an episode tree data structure, pruning less frequent episodes from the episode tree, analyzing the episode tree to identify frequent episode rules, and applying the frequent episode rules to future interactions with users.