Refractions Research was originally the sole developer of PostGIS. Now that the project has grown and expanded, there is a large community of contributors and a Project Steering Committee that leads the project. All the latest software updates and documentation can be found at the community website Postgis.net
PostGIS is a spatial database extension for the popular PostgreSQL object-relational database . PostGIS “spatially enables” the PostgreSQL server, allowing it to be used as a back-end spatial database for geographic information systems ( GIS ) and web-mapping applications in the same manner as Microsoft's SQL Server Spatial and Oracle's Spatial database extension.
MapTools.org