It is well documented that virtual worlds today are applied in both educational and commercial teaching and learning contexts. Where virtual worlds were once the reserve of entertainment, they have now taken on a variety of roles as platforms for business meetings, simulation, and training and education. In this context, the integration and interoperability with both online and offline resources and technologies is important. In this paper, the authors review progress toward increased integration and interoperability from the first virtual world games to today’s virtual world platforms. This paper highlights opportunities that will arise from further improvements in the ability to create virtual world platforms, content and activities that are truly interoperable, as well as more significant challenges along the way.