Laws of Lashon Hara / 2: 12-13 (35)

12. It is forbidden to say about a lecturer that his lectures are boring, even if this is true.

13. One who confides a business or trade secret to three people, it is permitted for them to tell others, even if this might cause him harm. This is true, only if none of the three are considered to be God fearing, a relative or close friend of this individual, as he will definitely not pass it on. So too, they cannot stress the issue, in a way that can cause him harm. Also, this is only as long as he didn’t ask them to keep it secret]. However, one who heard it from the original three listeners, it is forbidden for him to pass it on.