16. A computing device comprising: a memory; and a processing device coupled to the memory, wherein the processing device is to: receive a request for a user interface (UI) document comprising a first set of media items, wherein a set of identifiers is associated with the UI document, the set of identifiers comprising a page identifier for the UI document and one or more identifiers of the first set of media items; obtain an identifier list for a second set of media items in a social share included in the UI document; compare the set of identifiers for the UI document with the identifier list for the social share to determine one or more media items in the second set of media items that are represented on the UI document; update the identifier list by removing identifiers of the one or more determined media items that are represented on the UI document; and modify the UI document to provide a representation associated with a first identifier from the updated identifier list for the second set of media items of the social share.
16. A computing device comprising: a memory; and a processing device coupled to the memory, wherein the processing device is to: receive a request for a user interface (UI) document comprising a first set of media items, wherein a set of identifiers is associated with the UI document, the set of identifiers comprising a page identifier for the UI document and one or more identifiers of the first set of media items; obtain an identifier list for a second set of media items in a social share included in the UI document; compare the set of identifiers for the UI document with the identifier list for the social share to determine one or more media items in the second set of media items that are represented on the UI document; update the identifier list by removing identifiers of the one or more determined media items that are represented on the UI document; and modify the UI document to provide a representation associated with a first identifier from the updated identifier list for the second set of media items of the social share. 20. The method of claim 16 , wherein the social share is at least one of a post submitted on a social network site, a comment submitted on the social network site, a post submitted on a content hosting site, or a comment submitted on the content hosting site.