1. A method of providing content, performed by a client system having one or more processors and memory storing one or more programs for execution by the one or more processors, the method comprising: detecting execution of a mark-all-read command associated with a specified stream to which a user of the client system has subscribed, wherein the specified stream comprises two or more content feeds including a first content feed for a first publication source with a first depth limit and a second content feed for a second publication source with a second depth limit, and wherein each respective content feed comprises a respective set of content items published by a respective publication source; displaying content items from each respective set of content items, including from the first content feed and the second content feed, in a single merged list of content items that includes content items from the first publication source up to the first depth limit and content items from the second publication source up to the second depth limit, wherein the single merged list of contents items is sorted by content item timestamps and displays, for each respective content item, a title and wherein user selection of a respective content item toggles between expanded and compact modes of the respective content item; recording a time of execution of the mark-all-read command; for each respective content item associated with the specified stream, comparing a corresponding timestamp associated with the respective content item to the recorded time of execution of the mark-all-read command; and individually displaying the title of each respective content item in the single merged list in a first format or a second format based on the comparisons, wherein the second format is visually distinct from the first format, content items that are determined to have associated timestamps prior to the recorded time of execution of the mark-all-read command are displayed in the first format, and content items that are determined to have associated timestamps after the recorded time of execution are displayed in the second format.