I'm still not sure if this would end up being a good or bad thing for Amazon, in terms of sales. With the stacking glitches and other issues, the ECA was probably costing Amazon some money. Of course, you also have to put some blame on Amazon's own IT department for not being smart enough to prevent such exploits. Even without the glitches, the 10% off could be combined with pre-order bonuses, price match guarantee, and even Gold Box discounts to create some pretty awesome deals. All of that had to be cutting into Amazon's profits. Then again, without all of those things, people would probably just go back to buying used games, keeping new games from Gamefly, using Goozex, etc...
I think most people were using the codes as intended, though, and I imagine that it was sending Amazon a lot of game & accessory business. I started buying games almost exclusively from Amazon and probably have 15 or more pre-orders placed with them right now which utilize the ECA discount. I wouldn't have placed a single one of those without the extra 10% off, I'd have just waited and rented them from Gamefly, then kept them if I thought they were worth owning.
I guess the question is, does Amazon actually make any money when you buy new games for about $48 shipped, then get pre-order bonuses on top of that. I think this sudden disappearance of their affiliation with the ECA is probably the answer to that question.
