The study revealed shifts among the top sites in 2007 -- due in part to new strategic partnerships.  While the information presented by Comscore does not take into consideration activity on the main search engines (which is where a bulk of the local query volume comes from) it does provide us insights into the relative success of these networks when analyzed by themselves.

From the release: Yellowpages.com Network (20.2 percent share) edged out Superpages.com Network (20.0 percent share) in Q4 2007 to lead the IYP search market. Like Yellowpages, Superpages’ new partnerships provided a boost to its search activity, with the new Local.com relationship and the Infospace FindIt/Switchboard.com acquisition contributing to its gains. However, Superpages discontinued its affiliation with both 411.com and MSN Yellowpages, offsetting the positive impact of the new relationships. Although Superpages saw an increased number of total searches in 2007, it did not grow as fast as the market, and as a result its share fell slightly.