It is sad to hear that. Whenever a website experiences this, things could be really frustrating for all the people involved. Just imagine a big online store getting hacked. The experience for customers could be really bad. the management may also panic as well.
It's very unfortunate that the forum is facing a very serious DDoS attack and that's never good for business. They haven't really been upright in how they have treated most of their loyal staffs. This is a very clear indication they are being targeted by someone who had it for them for a long time.