Oh, one other feature I'd like: prediction confirmation & statistics. Plenty of news stories & opinions declare "X says Y will happen by date Z"; I'd like to mark keyword Y for followup, either reporting that it actually happened or that date Z came & went (or, say, it happened but a couple weeks late), and in the long term document X's success rate as a prophet. Lots of predictions get made in the news media, but nobody ever holds 'em to it.
That sounds interesting. Not sure the most effective way to implement something like that but i'll definitely think about it. Thanks!
Most effective way is a prediction market, but it's hard to create a legal one.