1 The paper proposes a new test model, Call-For-Testing (CFT), and applies it to User Acceptance Testing (UAT) of Web Applications. Different from traditional approaches, UAT in the context of CFT only means beta-testing on the site or field, i.e., by customers or end-users, and does not include alpha-testing which is supervised or performed by the system provider. CFT model leverages open community resources for UAT. To guarantee the quality of CFT-oriented UAT, not only do we develop competent testing techniques/tools for community testers to perform UAT, but also a testing auditing mechanism is built up. We develop a CFT platform that constructs coverage criteria based on user requirements and design documents, monitors community testers activities in real-time, and verifies their performances. Experiments are performed to evaluate the validity of CFT.