1. A method of enhancing search results generated in response to a search request, comprising: receiving a set of search results, wherein the search results list a ranked set of entries, each entry referencing a data object accessible over a network; identifying, by operation of one or more computer processors, metadata associated with a first user submitting the search request, wherein the metadata identifies at least one entry in the ranked set of search results, wherein the metadata associated with the first user includes at least one bookmark, wherein the bookmark is associated with a second user, wherein the metadata further includes one or more tags characterizing content of the at least one entry in the ranked set of search results specified by the second user, wherein the first user and the second user are associated by a common user group, and wherein the users in the common user group are associated with metadata data describing a common interest of the common user group; determining a current network quality of service available to the first user; adjusting, by operation of the one or more computer processors, the ranking of the entry, based on the metadata and based on the current network quality of service available to the first user, wherein the adjustment either increases or decreases the ranking of the entry; and returning the ranked search results to the first user.
2. The method of claim 1 , wherein the bookmark is retrieved from a social-bookmarking site, and wherein a plurality of users each contributes a respective set of bookmarks to the social-bookmarking site.