1. A method comprising: retrieving a plurality of related content items that are related to a user in an online service; identifying a plurality of topics of interest to the user using the plurality of related content items; ranking the topics by relevance to one of a plurality of content items in a stream of content and based on a relationship between an author of the topics and the user; associating an identified topic to a content item in the stream of content where the identified topic is ranked as being relevant to the content item; generating a marker for the identified topic; generating a user interface including one or more tiles and the generated marker rendered with a tile of the one or more tiles, the one or more tiles being an element on the user interface, and each of the one or more tiles corresponding to the content item of the plurality of content items in the stream of content; detecting a cursor movement towards the marker; in response to the cursor movement towards the marker, updating the user interface by expanding the marker in size to reveal an overlay of the identified topic on the tile; receiving a selection of the identified topic by the user; in response to the selection of the identified topic, replacing the tile with at least one of the plurality of related content items on the identified topic such that the user views related information when viewing the stream of content without having to transition to a different element of the user interface; and providing the user interface for display.