Using some of the recommendations here, including documenting solid applications of the data, and a 'social network of users' will help to establish and document the 'value' of data by the importance and diversity of data use. Documenting requests for data as has been suggested by others can help with this and some agency agency perceptions(with all due respect) that "numbers" of data sets proffered satisfies the criteria for 'importance' or 'value'. This should be the new day envisioned in public data availability.
Idea No. 127