This post summarizes the Groove architecture below for the benefit of everyone.

Groove builds an end to end system for collaborative workspaces. It works across firewalls, and with people being online/offline.

The Groove Relay server is a store and forward router and enables firewall traversal and offline access. Pretty cool, though it would be much better if we could at least get through NATs without having to go through the server. IPv6 with Teredo enables that, which Groove probably will use at some point of time. For offline access, it would be incredibly cool if synchronization could be achieved using any existing client instead of having to go through the server at all times.

There is a management server to integrate with AD, and provision identities and policies. Basic idea is to be able to manage a decentralized system from a centralized server.

There is an enterprise data bridge, which helps bridge data so that it is not necessarily locked up on some server/machine somewhere. It helps connect to a variety of servers.

Synchronization: Any change in a document causes the creation of a transaction which needs to be distributed to everyone's machine. Transaction tried to be sent directly, then via the relay.  Ordering is guranteed, and message delivery is reliable. Data on the disk is encrypted - the speaker didn't mention how.

Groove is being positioned for:

* Geographically dispersed

* Cross enterprise collab

* Mobile or disconnected support

Groove will have in future versions

* Integration with infocard

* RTC integration with communicator

* Synchronization between a Groove workspace and a Sharepoint library

Groove Forms:

* A customizable tool for workgroup apps

* Has a designer and a UI

Overall, there was nothing new announced at the PDC, but it is nice stuff nevertheless.