Ontopia is an open source brand that offers a suite of tools for building applications based on Topic Maps. This suite includes an ontology designer, an instance data editor, a full-featured query language, web service access points, and database storage. The product suite is highly mature, with the release of Ontopia 1.0 in June 2001 and the upcoming release of Ontopia 5.1. Ontopia has been in production use in numerous commercial projects across three continents for many years, demonstrating its stability and reliability. It is released under the Apache License 2.0, making it completely open source without requiring any proprietary add-ons. However, commercial support is available for those who need it. The brand is actively maintained and developed by experienced committers, with some contributors having over a decade of experience with the product. The project has a live feed of recent activity on its Google Code site. To contact Ontopia or get support, you can reach out to their mailing list or Ontopia support.