http://blog.humblebundle.com/post/107906804069/changes-in-steam-key-redemption
A little over a year ago, we launched OAuth Steam key redemption, creating
one-click Steam key redemption for games purchased through Humble Bundle.
However, Steam is removing support for OAuth, so we’ll be returning to the
system we used before, which requires you to manually redeem your Steam keys.
Starting today, go to your Steam desktop client and use the "Activate a
Product on Steam" feature to redeem your keys.
For more details on how this process works, please check out our support page!
一年多前，Humble Bundle使用了OAuth，一种在Steam领取游戏的认证方式，
只要一键就能将从Humble Bundle网站上买的游戏领取到Steam。
然而，随着Steam即将移除OAuth的支援，我们将回归原先使用的系统，
也就是你必须手动将序号输入到Steam上。
从今天开始在Humble Bundle买的游戏，
就必须在Steam主程式的左下角 "+ 新增游戏…" 输入序号来新增。