Past lawsuits have involved suing over publication of private intellectual property in the form of church teachings. However, as a result of one of their lawsuits, a good portion of that entered the public domain when it was entered as evidence in the court case, so I don't think they can fall back on that anymore. They seem to be very creative when coming up with their grounds, though. Even so, you needn't have solid grounds to sue someone, just deep pockets, if your intent is to ruin the person you sue.