At my "day job", Dun & Bradstreet regularly offers to sell us credit and ownership information on other companies we deal with. I asked a couple of pals who work at big companies about our own records, and one of them got me our information. It was 60% inaccurate at least. I examined the payment record, which detailed specific amounts at specific times, and the number of days we had paid in, and I was able to narrow it down to three companies that were feeding D&B information about us. From then on, I knew I could pay everybody six months late and still have a perfect rating if I'd pay 3M and the other two within 30 days (not that I cared, but you see what I'm saying).
Overall, i'm not impressed with them and their badly-researched Big Brother business strategy. From a trader's point of view, don't tell anybody anything ever -- unless you have found the Holy Grail, in which case, you should immediately PM me. But don't tell D&B anything unless they're paying you more than your privacy is worth.