When you figure out what it is, you may find you don't have the right data because you weren't asking the right questions, but you sure have the information security liability that goes with it whether or not there is any upside.

There are lots of ways to structure a database that will make whatever information you collected useless or worse than useless for your intended purpose once you figure out what you need to know.

I am inclined to agree with the article. If you aren't actively using it currently, why keep it?