We need to remind them of their responsibility to the organization by accurately documenting the use of data. In a sense, it's very similar to the user's responsibility for managing the security of his or her data. Second, pick a methodology and stick with it. Don't abandon it after a few months. As if documentation has no value.
Methodologies can be formal or informal.
As a consultant, I believe in formal methodologies, but if you disagree, don't let it stop you from implementing a modest one. Concentrate on the data's accuracy, clarity, relevance and consumers. Finally, make it accessible. Your local library is understandable to everyone from grade schoolers to graduate students. Your developers and DBAs should remember that data needs to be published, as well as cataloged and archived.