Well, the claims are that it's to "stop hacking & duping". The real main reason is likely that they want everyone dialed in (and, yes, duping gotten rid of) so that they can funnel everyone into their "Real Money Auction House" and rake in the transaction fees.

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re: startup problems - yep, between the servers only opening up at 3am east coast, and the inevitable login problems, I wasn't particularly upset that I wouldn't be getting the game until sometime today.
