This paper presents a new peer-to-peer (P2P) file-sharing system called Gia, which aims to improve the scalability of existing P2P systems like Gnutella. Gia retains the simplicity of an unstructured system while significantly enhancing its scalability. The authors propose several modifications to Gnutella's design, including dynamic topology adaptation, active flow control, one-hop replication of pointers to content, and a search protocol based on biased random walks. These modifications are designed to dynamically adapt the overlay topology and search algorithms to accommodate the natural heterogeneity in P2P systems. The paper includes simulations and a prototype implementation to demonstrate the effectiveness of Gia, showing a three to five orders of magnitude improvement in total system capacity compared to Gnutella and other decentralized systems. The design of Gia is built on previous research, but it is the first open design that combines all these elements and explicitly accounts for capacity constraints. The authors also discuss why Distributed Hash Tables (DHTs) are not suitable for P2P file sharing due to their limitations in handling transient clients, keyword searches, and the prevalence of well-replicated files.This paper presents a new peer-to-peer (P2P) file-sharing system called Gia, which aims to improve the scalability of existing P2P systems like Gnutella. Gia retains the simplicity of an unstructured system while significantly enhancing its scalability. The authors propose several modifications to Gnutella's design, including dynamic topology adaptation, active flow control, one-hop replication of pointers to content, and a search protocol based on biased random walks. These modifications are designed to dynamically adapt the overlay topology and search algorithms to accommodate the natural heterogeneity in P2P systems. The paper includes simulations and a prototype implementation to demonstrate the effectiveness of Gia, showing a three to five orders of magnitude improvement in total system capacity compared to Gnutella and other decentralized systems. The design of Gia is built on previous research, but it is the first open design that combines all these elements and explicitly accounts for capacity constraints. The authors also discuss why Distributed Hash Tables (DHTs) are not suitable for P2P file sharing due to their limitations in handling transient clients, keyword searches, and the prevalence of well-replicated files.