Loosely coupled grids allow straightforward resource sharing because resources are accessed and exploited through de facto standard protocols and interfaces, similar to the Internet's early stages. The loosely coupled model allows easier, scalable, and compatible deployment at a lower global performance expense, compared to a tightly coupled alternative. Because we can apply the end-to-end principle only on both the client and server sides, we can build loosely coupled grid environments based only on Globus services and user-level middleware, while obtaining acceptable quality of service for both grid and local users, and fair resource sharing.