17. A system comprising: one or more processors; and a data store coupled to the one or more processors having instructions stored thereon which, when executed by the one or more processors, causes the one or more processors to perform operations comprising: obtaining, by the one or more processors, social context information about interactions of a plurality of users from a social graph, the social context information including social video content sources; generating, by the one or more processors and based on the social context information, social attachment information, the social attachment information for generation of annotations that indicate associations with social video content and a relation to one or more of the plurality of users; and storing, by the one or more processors, the social attachment information in association with a video search index.
17. A system comprising: one or more processors; and a data store coupled to the one or more processors having instructions stored thereon which, when executed by the one or more processors, causes the one or more processors to perform operations comprising: obtaining, by the one or more processors, social context information about interactions of a plurality of users from a social graph, the social context information including social video content sources; generating, by the one or more processors and based on the social context information, social attachment information, the social attachment information for generation of annotations that indicate associations with social video content and a relation to one or more of the plurality of users; and storing, by the one or more processors, the social attachment information in association with a video search index. 18. The system of claim 17 wherein the social attachment information enables identification of a video from the video search index that matches a search query and is socially relevant to a user that entered the search query.