The "no address" layer on qa.poole.ch now highlights landuse=residential layers that don't contain addresses. I originally intended to do this based on address density, but that doesn't seem to make a lot of sense at the current point in time.
Here an extreme example of how the new layer looks near Atlanta:
You can see bits of green on the above map from the new "has address" layer that highlight buildings and nodes with addresses. With the B&W backgroud you can get a good overview of where we actually have addresses:
More information can be found on the wiki.