1. A computer-implemented method for generating a ranked list of resources in response to a query, comprising: pairing the query with a plurality of microblog resource identifiers, wherein each microblog resource identifier comprises a resource identifier obtained from at least one microblog post, thereby generating a plurality of query/microblog resource identifier pairs; generating a feature set for each query/microblog resource identifier pair, wherein generating the feature set includes generating at least one textual feature 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; processing the feature sets associated with each query/microblog resource identifier pair in a first machine learned ranker to produce a ranking for each microblog resource identifier; and generating the ranked list of resources based on the rankings for each microblog resource identifier produced by the first machine learned ranker.