Meanwhile, interested in selling the system to other customers, GEIS developed both DOS and eventually Windows based versions of the client software and sold the system as "DealerTalk" starting in 1986, aiming at the Apple model of manufacturers using the system to communicate with their dealers. All the systems, including the AppleLink community, were united behind the scenes as part of GEIS' worldwide Quik-Comm E-mail service and could exchange mail with each other and all GEIS mail customers, using addresses like MICHAEL@APPLELINK or JOHNDOE@GEIS. This was later expanded to include Internet mail addresses. Eventually, the GEIS products were renamed BusinessTalk and after a complete system rewrite and creation of their own Macintosh client program (never incorporated into AppleLink), again renamed BusinessTalk System 2000 in 1992. During this time the system, with the Windows client, also became the foundation for Microsoft's first on-line service for developers, the Microsoft Partner Network (MSPN).