From avsforum.com:

AVS Forum has suffered a major failure in the database and backup storage. As such, we have no choice but to recover from August 2nd.

This represents tens of thousands of lost posts for the last week. There is nothing we can do about it at this time but move forward. We are sorry about the loss and will work to be sure this does not happen again. We are as upset about this as you may be, more than likely even more.

We will re-open as soon as can.

Regretfully,

AVS Forum

This is a pretty major outage and losing a weeks worth of posts has to suck. I wish them well getting things back up.

Ouch!

looks like they are back up already

I love the AVS forums, but stability has not been their strong point.

Really? I can't recall any previous lengthy outage or data loss that they've had.