The delay was due to two problems -- the pre-order load and the staff had caught a critical bug in the game at the last moment. The heavy volume of pre-orders had taken longer to process than Aventurine had anticipated, leading them to delay the launch so more pre-orders could be properly processed. Afterwards, they delayed the launch again due to the wish of the development team to fix that last bug.
The heavy volume of players interested in the game's release had crippled the forums, shooting traffic to over double what it was at the launch of beta. Aventurine made the decision to bring down the game forums, instead only displaying a message regarding launch status on the forums page. This, in turn, brought more people into the Darkfall chat room run by Stratics, overloading that server and forcing Stratics to temporarily bring down the official chat.
Aventurine plans to relaunch the forums sometime today, with the hopes that they can keep the system online under all the duress. All current subscribers (those lucky few with boxes) will be given 33 days of subscription time instead of 30 to cover for all the delays.