One major change required by Vista is an alteration to Google Talk's security model. In earlier releases, Google Talk automatically installed by default for all users of a machine. In line with Vista's enhanced security model, the default installation is now for a single user, though this can be changed at the time of installation.

Lining up ISV support has been a critical challenge for Microsoft ahead of the consumer release of Vista on January 30. While many applications should run without change, those which make assumptions about the security model, or access low-level kernel resources (anti-malware software is a typical example) have frequently required recompiling.

Microsoft is also keen to encourage vendors to take advantage of the new Vista Aero user interface, although the bare-bones approach of Google Talk doesn't make that a likely candidate.

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