Finnish National Geoportal Paikkatietoikkuna was first launched in 2009 and is now the home of over 3000 open map layers from nearly 70 different data producers in Finland, and is used by 3 - 6 000 users every day. Its background is largely in the INSPIRE-directive, which expects the spatial data to be accessible, reusable and interoperable: the Geoportal functions as a national service for the data producers to demonstrate and display their open datasets to the public. Paikkatietoikkuna is regularly referred to in social media, news articles, blogs as well as teaching materials in education sector, as it has become well known in the society. Today, Paikkatietoikkuna is essential for thousands of professionals in variety of different fields, such as in forestry and environmental fields. These people need in their daily work an easy to use map applications with national or local datasets for viewing and overlaying map layers for comparison, for creating their own map data for simple analysis or for embedding a map on their website without any programming skills. Paikkatietoikkuna, soon after its birth, initiated what is now known as open source Oskari map framework (oskari.org), and today many other map applications are based on Oskari. In this presentation you will hear how Paikkatietoikkuna gained its central role within Finnish spatial data infrastructure today.