The previous post including the letter written to William is important for legal purposes.  First, it shows William was informed of the lies and stories being told on I-dud to get people to buy more and hold on longer.  Second, William admits that the stories are nonsense and that there is a lot of disinformation being posted by some who claim to be in contact with him.

However, this letter is important for the story tellers as well.  If William really did provide inside information to them in private and super secrete meetings and phone calls, then William's response clearly states that he did not tell them anything.  This can be used in bother cases.