I'd like to see the Taskforce establish a whole-of-government Web Managers' Council similar to the US model.
This is NOT a group of CIOs/CTOs - whose primary focus is on the technological infrastructure - it is a group of hands-on Web Managers with direct responsibility for the effective delivery of government messages and management of online engagement and open data initiatives from a business perspective.
This group would be responsible for co-ordinating programs and support materials and providing senior advice on how to maximise the effectiveness of the internet for government agencies. AGIMO could facilitate and support the operation of this group.
An example of how this could be structured is available at: http://www.usa.gov/webcontent/about/council.shtml
I think establishing a Web Managers' Forum under it (similar to http://www.usa.gov/webcontent/community/forum.shtml) would be a positive step as well - considering that de facto organisations are already coming together on various social networks, but are not yet fully inclusive.
Note it would require the support of the Departments employing the individuals on the council, with an appreciation that there are whole-of-government objectives which sit alongside departmental goals.