Overlay network has emerged as a popular alternative to traditional client-server architecture for the distribution of media content. Intrinsic to the notion is a 'self-growing' community of end users. It is thus important to investigate practical issues in reality rather than following prescribed theoretical assumptions. This paper presents our research experiences on deployment of overlay network for live video streaming over Internet. In our implementation we adopt a gossip-based overlay construction protocol to accommodate topology changes and a composite scheduling mechanism to stream video contents. More importantly, with the service to totally more than 500,000 users and maximum 15,239 concurrent users provided by one common streaming server, we then exhibit insightful statistical results to reveal system performance and nodes properties in terms of capacity evolution, quality of service, request rate and online duration