You can select one of 9 heroes in the WarCraft universe, each with their own single hero ability, hero-specific cards and available-to-all-heroes neutral cards to battle other players in a random-but-fair matchup on Blizzard's own Battle.net to earn more cards and raise your ranks among other players.
Hearthstone will be free-to-play with random card packs available for real-money purchase. Though this might discourage some players, the game matches you up with opponents of closely identical deck (card value wise).
ALL cards can be bought with in-game gold which is earned by completing daily quests, winning a set amount of games and playing Arena mode. Furthermore, all cards in your collection can be broken down into "Arcane Dust", a form of material to create ANY card in the game.
Hearthstone is designed to streamline the tcg (trading card game) formula to provide equal parts fun and challenge to players of all levels. This is the current to-go entry-level battle card game for novice players.
The game was announced at Penny Arcade Expo, March 2013 and entered closed-beta in August 2013. Open-beta will begin from December 2013.
Hearthstone will be available for PC, Mac (currently available for closed-beta) and iPad. iPhone and Android version are expected Q4 2014.
Bill: Did you get all the GOLD cards?