Humble Bundle announced today on their Humble Mumble blog that Steam has removed support for OAuth, a tool that allowed Humble Bundle to provide one-click redemption of Steam games directly to a user’s account.
Removing support for the system means that Humble Bundle has to move their redemption system back to users manually entering keys into Steam’s client. While on the surface the main problem that this seems to provides in inconvenience on the consumers, is really a hole that has been opened for secondhand key distributors. When bundles are priced low, some users would snatch up extra keys to sell them through different re-sellers for profit, which effectively hurts developers for attempting to help charity.
There is no yet as to why OAuth is no longer supported by Steam or if Humble Bundle will pursue a new system to deter game key re-sellers until a new method is developed.