Potix Corporation is an open source software (OSS) company. The founders are Tom Yeh and Henri Chen. Before Potix, they had failed once and lost 25 million NT dollars. After the reflection, they determined to start a new company again. They developed an Ajax + Mobile framework named as "ZK", and adopted the OSS business model with an expectation to reach international market. ZK has been opened on OSS community since 2005 and become one of the most popular open source business applications on SourceForge.net. The users are from more 180 countries with more than 1.2 million downloads. Some business customers and users are from Fortune 500 companies that form a strong endorsement for a start-up firm like Potix. Volunteers in OSS community can either help develop core programs or new application, or help to translate user manuals to various languages. In addition, there are seminar held by academic or industry sections specific for ZK usage and experience sharing. Although ZK has excellent quality and is popular among worldwide programmers, the amount of licenses still retains a small percentage of downloads. The case is ended at the dilemma of founders whether they should split to OS version and business licensed version when they announce the next upgrade of ZK 5.0.This case provides three OSS issues for students to learn, including OSS business models, OSS community and how a start-up company as Potix to leverage the resources of OSS community to reach worldwide customers and enter international market.