Your site looks great so far... any way you can add the volume / last trades somewhere in Market Data?
It's on our list of things to do. We're brand new, so we don't have much trade history or volume anyway. We have some nice visualizations of market data in testing and will deploy them as things pick up.
If someone will receive a fee rebate for providing liquidity, wouldn't any rational trader factor this in to his or her trade, thus effectively eradicating the rebate?
I'm not sure what you mean... The entire point is for traders to factor the rebate into their trade, thus giving them an incentive to create tighter spreads.
Looking at the API docs, what are the acceptable values for productid?
Passed "1", which seemed to work, but didn't see anything in the docs about that.
1 is correct. Sorry for the confusion, we will document this better.