We looked around the world, because we were a little late to the game, and found that a lot of jurisdictions were taking a lot of flak because they were just dumping data sets that were easy to dump out there, but weren't really of use to people. That's why we went with the voting tool, so that the public could tell us what's useful to them. So that's the quality, “quality” meaning value to the individuals, the developers, or the community.
We also did it because we have a restriction in terms of how much money we can spend on opening up data sets. “Open by default” means all data will be released, and over time it will all be open. We'll get there. For us this is staging so that we can get the most valuable data sets out first.