To recap,

• First I talked about GFS, the very useful folder-synchronization feature in Groove V3. This puts Groove's collaborative-workspace features right into the Windows shell. Folders are workspaces.
  
• AppLauncher (part one) describes how to build the same type of integration into Any Windows App, so that YourApp has a Groove workspace underneath. The application is launched from Groove with a commandline saying how to access the workspace's services.
  
• AppLauncher (part two) shows the glue which binds "your application" into the Groove user experience.

Existing applications -- anything from off-the-shelf software to custom line-of-business apps -- can easily take advantage of Groove's collaborative services. They can inherit an easy, secure, robust, decentralized way to share state between several people in a "workspace". For example, if you have built a .NET (WinForms) application for a customer-support process, which accesses an Oracle back-end, this app can also be used in small groups with a "shared context".

You might use Groove's workspace services simply to store local data securely.

Or, more interestingly, you might put work-in-progress documents into a Groove workspace ("underneath" your app) so that multiple users can work with them as part of your larger process. Because the workspace is Groove, those users wouldn't even need to be online to have access to the shared data. They wouldn't necessarily even need to be in the same company.

So, that customer-service application might front-end Oracle... but you might want to invite the customer into your instance of the application to make a shared place for interaction. They wouldn't see the Oracle database, but your application might push some of the relevant status documents and data into the Groove distributed storage...

New applications can be built on the Groove platform without any really specialized knowledge. There's a very "regular" web-services API to communicate with Groove; the rest of the app is up to you. (Personally, I want to build some games...!)