The Vermont State Bar Association has issued an opinion on metadata mining, concluding that the practice is generally permissible.
To date, fourteen bar associations have examined whether lawyers should be permitted to engage in metadata mining. The opinions fall into three categories: some say the practice should almost always be impermissible (seven opinions -- Alabama, Arizona, Florida, Maine, New Hampshire, the New York State Bar, and the New York County Bar); some say it should almost always be permissible (three opinions -- ABA, Maryland, and Vermont); and some say that it should be permissible, but with some limitations (four opinions--Colorado, District of Columbia, Pennsylvania, West Virginia).
In previous posts, I had broken the list down into two categories, but after looking at the opinions more closely, I think they really fall into three.