This document proposes a new targeted crowdsourcing system that leverages Google's large user base through advertising to collect knowledge from users. It finds knowledgeable users can provide high quality answers more efficiently than paid workers. The system uses quizzes with calibration and collection questions to assess user competence without monetary rewards. Immediate feedback and showing others' performance increases participation. Leaderboards had mixed effects. Citizen science applications could attract free participants through Google Ad Grants. Overall, the system engages unpaid expert users for crowdsourcing in a cost-effective way.