a hidden tax many customers don't notice

There are many details of Intrade that encourage a long-shot bias. These may be "hidden taxes," good for Intrade's bottom line, but I suspect that the long-shot bias is also, in itself, good for Intrade.

It's nice that Intrade generates the positive externality of information, but if we want better information, it's not surprising that we'd have to pay for it, such as providing other revenue streams than these hidden taxes.