1. A computer-implemented method comprising: storing, in a bookmark database, resource identifiers for a first user; receiving a request by the first user to expose, to a second user, a particular resource identifier that is stored for the first user in the bookmark database; exposing the particular resource identifier to the second user; storing the particular resource identifier for the second user in the bookmark database; receiving a search query from the second user; generating a result set based on searching a global index and resource identifiers that are stored for the second user in the bookmark database, wherein the result set includes the particular resource identifier; and outputting the result set.
1. A computer-implemented method comprising: storing, in a bookmark database, resource identifiers for a first user; receiving a request by the first user to expose, to a second user, a particular resource identifier that is stored for the first user in the bookmark database; exposing the particular resource identifier to the second user; storing the particular resource identifier for the second user in the bookmark database; receiving a search query from the second user; generating a result set based on searching a global index and resource identifiers that are stored for the second user in the bookmark database, wherein the result set includes the particular resource identifier; and outputting the result set. 9. The method of claim 1 , wherein receiving the request by the first user to expose the particular resource identifier comprises receiving a request by the first user to share the particular resource identifier with one or more users identified as a social network connection of the first user, and wherein exposing the particular resource identifier to the second user comprises determining that the second user is identified as a social network friend of the first user, then exposing the particular resource identifier to the second user.