I will speak on their behalf, since I know the answer.
PADI - Has been offered a forum, and they have been discussing it internally. Their "hang up" is - determining who at PADI would respond for them, and they're also worried that they could be inundated with questions, which would pose additional challenges. I have patiently waited for them to reach a decision on their own about this, and respect that in larger companies, it's sometimes difficult to reach a conclusion about some matters quickly and easily. PADI and I have spoken about this several times however, and it's still a strong possibility in the future.
DAN
1) Did have a Q&A Forum here on SB. They (after long internal debate) concluded that the forum itself was actually a detriment. DAN, as an insurance company, is bound to certain laws. They cannot discuss personal information, or give insurance advice on the internet. What applies to one person may have circumstances for others. The end result would be; people asking questions, to which a representative from DAN would reply, "to answer that question, you should call DAN".
B) People were asking medical advice in the DAN forum. People would actually post questions like, "Dear DAN, I was diving 2 hours ago, and now I have tingles in my fingers; what should I do? I await your response." Again, the only answer DAN could give would be, "Call DAN and/or Call your doctor"
Ultimately, what is the use of a Q&A Forum, when the only "A" would be "Call DAN"? I can understand this position, and agreed with DAN that removal of the forum would probably be in everyone's best interest.
If anyone else tells you otherwise, they really don't know. I am the director of Sales and Marketing for ScubaBoard, and I am the one who has spoken to the people at both, and I am the one who pulled the plug on the DAN forum when the decision was made. I share this publicly, to be purely transparent with our users, and since I don't think that any top secret information is being disclosed.