Seems to be a very low cost, low tech water purifying system for developing areas.

watercone website

Can you use this as a sun-hat and still purify water? Or better: as a rain purifying hat !

I think it has potential on the scale of Giza pyramids.

Yet another solar still.
I think it is a great idea for poeple that live in sun blasted coastal desert areas.
I suppose it would function anywhere you have lots of strong sunlight and dirty water to work with too.
I wonder how strong the sun has to be for it to destill enough water to be effective?
It is a nice item and I am glad to see it.

Mass-Marketed solar still.
COOL idea for sure.

I think it looks great. It could be sped up by putting a cup of boiling water that needs to be distilled under this cone. Or lifting the cone a little bit above the ground and placing a stove with a cup of boiling water underneath. Assuming that the plastic can withstand high temperature without leaving some bad stuff in the distilled water.

Looks like a variation on the SOLAS survival at sea that's been around for decades.

Completely ineffective (as I understand the matter) at sea because of wave action.

Biggest issue that I have with it is how much water does it produce, and how many do you need per person?

I think that a large scale version might have possibilities. Per square foot of ground, a large version would be more efficient. In fact, I cannot see any reason why it has to be round rather than square or oblong.

The sticking point for me about a lot of these solar de-salination ideas is why haven't they been used more extensively in the middle east? Lots of sun, lots of capital, very expensive water. There must be a major flaw somewhere if it's not economical to run them there.

Well that´s interesting point. Maybe somewhere where is not true free market someone doesn´t want to see this happening and wants to keep the price of the water high. Maybe there is other issue. I don´t know.
Recently I saw documentary A World Without Water. There were some people that had to use dirty water. I was thinking that several pieces of this cone or something similar would make a big difference and wouldn´t cost too much if it works as advertised.
I also donate some money to organizations and projects that should help a good thing from time to time and after watching this documentary I immediately sent some money to one of these projects that is designed to help in the areas without water because what I saw was quite rough and sad.

I don´t see the size of the cone as a problem. You can catch up the size with big number of the units. Big cones would be harder to manipulate.