This thread was established to keep track of the two incidents.
1) Bitcoin-24.com suffered a attack on 31th of October 2012 (announced):
http://bitcoin24.zendesk.com/entries/22278332-mysqli-31-10-2012-server-attackThe maintainer had a strictily limitied hot wallet, which made it sometimes cumbersome for users to withdraw coins but should have limited the damage. He is willing to compensate everbodies losses, which the intruder managed to inflict by stealing the API-Keys that where enabled by default. It seems that the exchange itself didn't suffer any large damage in confidence since losses are compensated and business is back to usual. Only the API feature will be disabled for a while.
2) At the same time bitcoin.de is unreachable for at least about an hour, no further informations found. Maybe just maintenance work, but you never know.
UPDATE: At least apache is back online:
www.bitcoin.de:
It works!
This is the default web page for this server.
The web server software is running but no content has been added, yet.