At the Campfire One event last night, Google launched the Google Apps Marketplace and demonstrated how external Web applications from other vendors can be integrated into Gmail, Google Calendar, Google Docs, and other services that are part of the search giant's Web-based productivity suite.

In the quest for data liberation, Google's hosted Web services have long offered a wide range of APIs for third-party developers. With the launch of the new marketplace, however, Google Apps for domains is opening up even further and enabling external software to expose its own functionality directly through Google's Web-based applications. This will make it possible for third-party software in the cloud to offer broad interoperability with Google Apps and very tight integration.