FWIW, IMO etc. LOL.
Yes, most "rebate trading" in the older sense (ala Swift etc. ) pretty much ended in late 2009 with all the HFT "interference" and Flash orders etc. Our traders pretty much stopped "parking orders" - no real reason to provide liquidity when we could be "leaned on." We chose to hit bids and take offers at the cheapest destination. That paid off of course.
Now, with the "inverse ECN's" who pay us to take liquidity, we use smart routing to take advantage of both sides - this is paying off extremely well.
I am about 75% through with an article for TASC about all this. I have interviewed CEO's and others from the various exchanges, ECN's and market centers. Hope to be done early next week for April publication.
As I said, FWIW...
Don