Search Commons does not collect any information about its users or search queries. However, Search Commons uses Google Custom Search for handling search requests. Search requests are sent to Google servers from the user's browser. This data processing is regulated by Google and its privacy policies.
Also Custom Search makes certain aggregate data available to Search Commons and does not allow to disown this data. The data is the total number of queries and the list of popular queries. It is aggregated at the level of a search engine and does not contain personally identifiable information. You can find more information in the Google Custom Search documentation.