It required a network adaptor, which was available as an add-on for original models and integrated into the hardware on slimline models. However, Sony provided no unified service for the system, so support for network features was specific to each game and third-party server, and there was no interoperability of cross-game presence. Five years later during the development stage for its third home console, the PlayStation 3, Sony expressed their intent to build upon the functionality of its predecessor by creating a new interconnected service that keeps users constantly in touch with a "PlayStation World" network.[4] In March 2006, Sony officially introduced its unified online service, tentatively named "PlayStation Network Platform".[5] A list of supporting features was announced at the Tokyo Game Show later the same year.[6]