Quote from IBsoft:
Our relationship is (for now) limited to liquidity-taking.
Please note that our Smart router gives you some of the benefit you seek. If you post a non-marketable order (which we route to a venue) and IB then subsequently receives a liquidity-taking order for the same stock, we will cancel your order at the venue and cross the two orders within our platform. Hence, your order provides liquidity to IB customers.
And these executions show up as SMART on the trade window?(I'm referring to both the dark pools executions and this execution that you referred)