28. The system of claim 21 , further comprising: receiving input requesting that the second search query be submitted to the second search query to the second search engine; and in response to receiving the input: providing the second search query to the second search engine, and displaying a plurality of search results received from and determined by the second search engine as satisfying the second search query in the user interface.
29. The system of claim 28 , further comprising simultaneously displaying the plurality of respective search results determined by the first search engine as satisfying a first search query in the user interface with the plurality of search results received from and determined by the second search engine as satisfying the second search query.