The report does not state the exact criteria required to be counted as a registered player, so you can feel free to endlessly debate exactly how much of a success this makes Hearthstone overall. But there’s not much space to debate whether or not it is a success. And if this makes you want to log in and play, well, we certainly can’t blame you, not with the whispers of Yogg-Saron caressing our mind, haunting our dreams, beckoning us toward great plateaus of abandoned hope and cards from which a scattering of mana crystals can be heard clattering forever.
Source: Press release via Blizzard Watch