1. A system comprising: a server computing device; and a computer-readable medium coupled to the server computing device and having instructions stored thereon which, when executed by the server computing device, cause the server computing device to perform server-side operations for distributing digital content for display across a network, the server-side operations comprising: serving one or more web page documents to a client computing device operated by a user, each document containing instructions for a browser application to perform client-side operations, comprising: displaying, within a web page of a plurality of web pages, a graphical representation of a content sharing interface of a first social networking service, the content sharing interface comprising a content input area to which user input can be received; receiving first user input to the content input area; in response to the first user input, expanding the content sharing interface within the web page to include an expanded content input area and a distribution interface, the expanded content input area displaying a graphical representation of digital content that is to be distributed; receiving second user input to the distribution interface, the second user input indicating one or more contacts to which the digital content is to be distributed; in response to receiving the second user input, displaying one or more icons within the distribution interface, each icon of the one or more icons being a graphical representation of the one or more contacts; receiving third user input to the content sharing interface, the third user input comprising a user instruction to distribute the digital content; and in response to the third user input, transmitting a post data set to the server computing system, the post data set comprising digital content data and distribution data.