1. A method comprising: receiving, at a server in a computer system and from a first user, a query to perform a search for user-interested information, the query including query parameters; obtaining, at the server and in response to the query, a plurality of search results based on the query parameters, the search results including the user-interested information; perturbing, at the server, at least a portion of the search results based on a perturbation criterion to generate a first set of perturbed search results; and serving, by the server, the first set of perturbed search results to the first user.