Certain embodiments involve optimizing how interactive content is arranged in electronic communications. A processor identifies a subject matter type associated with first and second online content items having respective first and second presentation types. The processor determines that a client has previously interacted more extensively with online content having the subject matter type and the first presentation type as compared to other online content having the subject matter type and the second presentation type. The processor selects a layout for an electronic communication for accessing the online content items based on determining that the client interacted more extensively with online content having the first presentation type. The layout displays a first portion for accessing the first online content item more prominently than a second portion for accessing the second online content item. The processor presents the layout via an interface for editing the electronic communication.