I agree, it would be interesting to have more results than just right vs. wrong.

Exempli gratia, with Scoble, one prediction was arguably half-right (minus the stylus pen, the iPhone essentially qualifies), one that was correct at a later date (as Joe said), one that is marked correct already (RSS becoming mainstream), and one that is simply wrong (re: friendfeed).

I also agree that selection bias could skew results badly, but the idea overall is excellent.

Also, props for the disclaimer on the page! "Past performance is no guarantee of future results." Almost hofstadterian levels of indirect self-reference.