I had this discussion with my manager once. I was of the opinion that there is no need for secrecy, which is why we were very forthcoming with the stats about reddit. However, he had one pretty good reason to keep financials and other stats secrets: It gives your competitors information they may not otherwise have.

For example, one stat is cost per unit. If your competitor knows that your cost per unit is say only 1% more than theirs, then they know how to undercut you to hurt your business.