We studied how a source expertise indicator impacted users' information seeking behavior when using a system aggregating diverse opinions, and how it interacted with a source position indicator to shape users' selectivity of information. We found that, for both attitude consistent and inconsistent information, the expertise indicator increased the selection of sources indicated to have high expertise and decreased that of low expertise. Moreover, when both source expertise and position indicators were present, users' selective exposure tendency, i.e., preferential selection of attitude consistent sources over inconsistent ones, decreased among expert sources. Moreover, we found that the expertise indicator could benefit encouraging common ground seeking with different others by increasing the agreement with, and perceived expertise of inconsistent sources indicated to be experts. Design implications for moderating selective exposure by highlighting the utility of dissonant information were discussed.