I can say that when the site came back up briefly, I did see my funds there.
Any senior members who did not create an account today, able to verify this?
I don't know how relevant this would be.
The funds aren't kept in the BTC Address we deposit them too.
Instead, once we deposit, our account is "credited" with numbers representing how many bitcoin we "own" in the system's larger pool of Bitcoin.
Let's say hypothetically all of BitBook's funds in that main pool were stolen in the attack (I hope not), then our account balances would still remain the same as those are only credits, not the physical coins.
Even if BB ran with all the coins (very unlikely IMO), the acct balances would remain. It's meaningless without anything in the site's withdrawable wallet.
On the other hand, if it is just a regular DDoS attack not associated with TX Malleability, then our coin are probably safe and the account balances that were seen during the back-up site reflect how much we will all hopefully be getting back soon.