Normal IHUB convention is a buy(green) when transaction is at or closer to the ask....sell(red) when at or closer to the bid...and black(?) when exactly at the midpoint between the bid/ask....
it looks like your ticker is at no bid x .0001 so no way for the software to compare---hence the ?....kinda like you can't divide by zero :-)
If it is Ihub platform you are questioning, their own explanation is this:
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=81336092&txt2find=dead|centre The 'Buy', 'Sell' and '?' columns - Where the 'Price' is closest to the 'Offer' price, the trade is considered a 'Buy'. Where it is closest to the 'Bid' price, the trade is considered to be a 'Sell'. Where it is dead centre between 'Bid' and 'Offer', it appears in the '?' column; this indicates that the trade cannot be identified as either a 'Buy' or a 'Sell'.