[ZenGum]

This is great, but there a few things I'm wondering about.

Do they plug the necks of the bottles? If not, wouldn't it get all gungy in there? dust, spiderwebs, moisture, algae ... also, if the necks were outside, when the wind was just right you'd get a wind-splitter effect, leading to amazing whistling noises. Might be fun ... for a short while.

EDIT: I have just noticed how the necks of the bottles nest snugly into the base of the next bottle. Very suggestively, in fact. You'd still get the issue with the corner ones, though. And do you really want your house smelling of stale beer?

Would it act as double glazing/insulation, even if the necks were left open? If they were closed, would there be expansion pressure problems?

I don't think this would be a good way of building a college dorm. Pretty soon some idiot with a baseball (or some deliberate hooligan with a baseball bat) is going to let fly ... hate to have to repair this.

Glass is relatively easy and economical to recycle. This re-use is cool, but not really heroic from an environmental perspective.

It's still cool though.