That's right - OAuth, a service used by sites such as Humble Bundle to authenticate with Steam to allow users to redeem games without needing the code, will no longer be supported. Oauth, which authorizes third-party access to Steam server resources without sharing their credentials, essentially removes a step when it comes to redeeming games on Steam.
One-click Steam Key redemption is really only in use by companies, such as Humble Bundle, that allow users to purchase Steam games to be redeemed on the platform. Put in place around a year ago, the service/API was aimed at making redeeming purchases easier - all users had to do was verify their account after hitting redeem for future purchases.
It's worth noting, for those interested, that OAuth is service that is complementary to, and therefore different from, OpenID.
Humble Bundle, as stated in the source link below, has been using OAuth for over a year now to the happiness of the community. The alternative to OAuth is simple, and something you likely already do when you redeem keys. Humble Bundle, and any others using it, will have to switch from allowing people to directly redeem without a code - to using code redemption again.
From here on out, when purchasing games from Humble Bundle, users will have to go back to getting a code to input into their Steam Client when they want to get new games. There's a full guide that they offer, but for those familiar with Steam, you'll just go back to hitting the "Games" tab, and "Activate a Product on Steam", followed by your code and the option to install!
While the downside is that it's an extra few steps to redeem your games, it's also easier to keep track of them, as well as have codes to give to your friends and family. While this doesn't affect old purchases, all new purchases will be giving users keys instead of the OAuth option.
While there's no indication as to why OAuth is being disabled within the post or on Steam's official pages, we have reached out for a comment as to why it is being removed.
Source: Humble Mumble (Humble Bundle Blog)
What do you think? Will this affect how you use Humble Bundle?