GroupDAV is an effort to create a "down-to-the-earth" protocol to connect OpenSource groupware clients with OpenSource groupware servers.
A major goal of GroupDAV is to keep the protocol as simple as possible and to stay focused on real world issues with OpenSource and free software applications.

KDE Kontact guru Cornelius Schumacher got interviewed during the Dutch KDE-PIM meeting. The interview contains a nice introduction into the motivations of GroupDAV and why it doesn't conflict with CalDAV [read it!]. Cornelius was part of the KDE team that joined with participants of OGo to create the first version of the draft.

The draft-01 is the very first version of the draft. It has a set of issues which need to get resolved - we will need some iterations until this is a sound document.
Be sure that you understand the limited scope of this effort prior drawing incorrect conclusions. You are invited to join our mailing list to ask any question you have.

GroupDAV has a very specific focus which is connecting the three popular OpenSource clients - Kontact, Evolution and Sunbird - with the broad range of OpenSource "groupware" servers. Whatever "groupware" means to the ~200 projects listed on Freshmeat.
This is a very specific focus because all the three clients have no legacy issues and are 100% iCalendar based while the far majority of the OpenSource servers started as RDBMS web applications which did not care about iCalendar at all.
Our goal is to connect them to native clients in a useful way despite their legacy issues. As an example consider the Bugzilla bugtracking system to expose its bugs as iCalendar tasks. Bugzilla can't represent a recurring task in the iCalendar concept nor does it feature alarms.
GroupDAV is supposed to deal with such setups in a graceful and pragmatic way.

This is an open effort and we welcome any feedback on our mailing list.