Described is a technology by which an interactive timeline user interface shows communication data aggregated from various sources (e.g., a telephone service, a website, an application and/or the like) in time order. To reduce the number of items in the timeline, certain items may be combined into a compressed item, e.g., items from the same source and/or of the same type may be rolled up into a rolled up item. The user may also interact to reply to a data item. For example, an editor may be provided upon interaction with a data item in the timeline, and the type of reply that is sent may automatically match the type of data item, (e.g., a text message reply to a text message).