After a game leaves beta, Blizzard typically removes all statuses earned during a game's beta. Is this going to be the same for cards earned during the beta phase of Hearthstone? Will all the work I am putting into collecting cards and leveling heroes be removed when the game goes live?
On October 2nd, 2013 Blizzard wiped all progress made during the initial Hearthstone closed beta. In the announcement post of the then impending wipe, Blizzard made it clear that there would be no further card wipes and hero leveling progress would carry forward into the release of the game. If you need more evidence read on.
From the aforementioned Hearthstone Account Wipe Incoming post:
Will there be any wipes in the future?
We don’t anticipate any further wipes. This goes for both the Hearthstone beta and after the game’s official release. Any progress made during the beta after the wipe will be retained through the release of Hearthstone, such as new cards you obtain, levels that you gain and ranks you achieve. Basically, you’ll now be able to keep your stuff.
If that does not alleviate your concerns the Hearthstone FAQ has further information concerning cards earned during the second phase of the Hearthstone beta:
Will the cards I earn or purchase in the beta test carry over into the live game? What happens if I purchased beta card packs for real money?
At this point in the closed beta, all purchases will exist in your game going forward. Also, as a thank you for testing out the in-game store during Hearthstone’s beta phase, everyone who purchased a card pack or entry into The Arena in the beta test will receive a Golden Legendary card, Gelbin Mekkatorque.
Finally, Aratil a "blue" (Blizzard community manager) on the Hearthstone forums had this to say about the potential for future Hearthstone card wipes:
There are currently no plans for another wipe.