"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," the statement reads. "We're close to the open beta - very close."
You can still secure your spot in the closed beta though - the same post explains that anyone who opts-in for the closed beta by January 7 will be invited in "at some point before the open beta begins." Anyone that signed up before December 16 for the closed beta but did not receive an invite should also check their spam folders, because Blizzard has sent invites to everyone that signed up before that date. If you can't find it, the post explains that Blizzard is constructing
While the closed beta is for PC and Mac, Hearthstone will reach iPad and Android devices in the second half of 2014.