19. A method for identifying resources in response to a query received from a user, comprising: storing resource identifiers extracted from a data stream of microblog posts in a microblog resource identifier index; determining whether the query is a recency-sensitive query; responsive to determining that the query is a recency-sensitive query, including resources identified by the resource identifiers in the microblog resource identifier index among resources to be searched based on the query; identifying resources among the resources to be searched based on the query; ranking the identified resources; and providing one single combined list of the identified resources to the user, wherein the one single combined list is ordered based on the ranking and at least one other ranking generated for a plurality of network resource identifiers, wherein each network resource identifier comprises a resource identifier obtained from resources other than the received data stream of microblog posts.
19. A method for identifying resources in response to a query received from a user, comprising: storing resource identifiers extracted from a data stream of microblog posts in a microblog resource identifier index; determining whether the query is a recency-sensitive query; responsive to determining that the query is a recency-sensitive query, including resources identified by the resource identifiers in the microblog resource identifier index among resources to be searched based on the query; identifying resources among the resources to be searched based on the query; ranking the identified resources; and providing one single combined list of the identified resources to the user, wherein the one single combined list is ordered based on the ranking and at least one other ranking generated for a plurality of network resource identifiers, wherein each network resource identifier comprises a resource identifier obtained from resources other than the received data stream of microblog posts. 20. The method of claim 19 , wherein ranking the identified resources comprises: ranking a resource identified by a resource identifier in the microblog resource identifier index based on at least one textual feature generated by analyzing text of one or more microblog posts that refer to the microblog resource identifier in conjunction with text of the query or generating at least one social networking feature by analyzing one or more characteristics associated with one or more microblog users that issued or received the microblog resource identifier via the microblog.