Ranking External Content Using Social Signals on Online Social Networks

In one embodiment, a method includes receiving a query to search for posts of the online social network; searching an index to identify one or more posts of the online social network that match the query, each post linking to an external object hosted by a third-party system, wherein the index includes a counter that records a number of social signals associated with each external object within the online social network; scoring each of the identified posts based at least in part on the counter associated with the external object linked to the post; and sending, to the client system of the first user, a search-results page including one or more search results, each search result including a reference to an identified post having a score greater than a threshold score.