The open government directive has specific requirements like the following:
Within 45 days, each agency shall identify and publish online in an open format at least three high-value data sets ... and register those data sets via data.gov... These must be data sets not previously available online or in a downloadable format.
Tracking those specific requirements on data.gov (separate from the open government dashboard which is broader) will help data.gov adoption by improving the quality and relevance of data available to developers and the public.
Besides agency compliance, it would be good to post a ranking of the most requested data on the dashboard.