Last week, Chinese Hearthstone servers temporarily imploded, causing a rollback of a few days. When the servers came back up, players discovered that their random card packs might not be so random after all.
Now that the dust has settled, Blizzard has compensated all Chinese players with 1000 gold and 15 card packs. The rollback was caused by a power outage that occurred during a routine maintenance. That is, evidently, a bad combination. Netease (the server providers) and Blizzard tried their best to restore the last data, but that proved impossible.
So instead, Chinese players get a fairly nice compensation package.