Blizzard is delaying open beta testing of Hearthstone: Heroes of Warcraft to ensure their upcoming virtual card game is ready for more widespread testing. They also announce that all those who applied for the closed beta before December 16th are being allowed in right now and that eventually plan on allowing all applicants into the closed beta, saying signups for this will end on January 7th. Here's the explanation from Battle.net:

With all of that said, we believe the right thing to do for the game is to not rush it out into open beta, but to instead hold onto it a little longer to make sure it’s ready for wider testing. At BlizzCon, we mentioned that we hoped to get the game into a state where it’s ready for open beta this month, but we’re just not quite there yet. The development team has been working hard to get this out before the end of the year, but our highest priority is that Hearthstone has an awesome launch when all gates are lifted and everyone can download it and play at the same time.

We’re close to the open beta—very close. And to enter this final part of our beta phase, we need your help. Keep trying out new decks, reporting bugs, and giving your feedback on our forums. That’s the best way you can help the team get Hearthstone into everyone’s hands as soon as possible.