Certainly not Chris Masse, says Emile Servan-Schreiber of NewsFutures:
[…] No, HSX box-office predictions are forecasts, not event probabilities, so if you restrict the definition to event probabilities, you exclude most of HSX. Same for “vote-share” markets at IEM. […]
Read the whole conversation (including the last Jason Ruspini comment) and decide for yourself. Now that Robin Hanson left us high and dry, who will write the broadest definition of prediction markets?