Many FOSS projects have started as endeavours to solve a problem at hand. In due course, the developed software has been adopted by some other users, has proven itself useful and then, by magic, has become a popular product with thousands of users worldwide. Fact or fiction? This presentation outlines the success story of Oskari and national co-operation around the software. Oskari http://www.oskari.org is a popular open source platform for browsing, sharing and analyzing of geographic information, utilizing in particular distributed spatial data infrastructures. The Finnish Oskari collaboration network actively works on various projects extending the software and creating new innovative services. The network consists of 27 member organizations, of which 12 are private companies. Success doesn't usually come without organized work. For the process of securing a successful co-operation, a few steps can be laid out. 1) Creating a useful piece of software with appropriate licensing 2) Co-operating with a number of early adopters 3) Starting a collaboration network 4) Adopting a sustainable model for collaboration and developing a product lifecycle management plan 5) Measuring success and providing proof of benefits of both the software and co-operation