I would love to see something that I’m calling a “prediction escrow service.” Basically it would work like this. You would register for an account. Then you could log predictions with the service, at which point they would be “locked” with a date-stamp. At any point after that you would be able to “unlock” your predictions and share them with a URL. The benefit of the service would that you could prove that you made a prediction at a specific point in the past.
The obvious use case would be technology punditry, but I’m sure other uses are possible.