The blog didn't reveal a specific date, but "authorized carriers" are now considered an indemnified party. Current developers have 30 days to accept the new conditions to the Android Market Developer Distribution Agreement (DDA), whereas new publishers are agreeing to them when signing up.
Adding carrier billing as an option should help developers move more copies of their apps. In the early days of Android, many users were less than thrilled with Google Checkout as the de facto way to make purchases. Two years later, Google Checkout makes more sense, but carrier billing will allow users to download an app and pay for it later. What's more, they'll have all of their wireless purchases in one convenient place.
It will be interesting to see what happens to application and game purchases once the terms go into effect. I believe there is a certain peace of mind with simply adding a few dollars to a bill that likely tops $100 a month already. On the other hand, we'll have to keep an eye on the process for refunding purchases.
Would you be more likely to purchase games or applications if you had the ability to pay for them later?