Efficient presentation of related messages in a computer network-based messaging system, including a message parser for parsing related messages into sub-messages, a comparator for comparing each sub-message identified by the parser to each sub-message in a set of unique sub-messages previously identified by the parser within any of the related messages, and adding to the set any of the sub-messages identified by the parser that are not members of the set, and a message presenter for marking with a visual indicator each of the related messages that contributes any sub-messages to the set, where the marked messages are visually distinguishable from all other of the related messages that do not contribute any sub-messages to the set.