Discussion on:

The design challenges of building floating cities, or 'seasteading'

this seems like a biosphere on water concept to me, but are they not sealed? why on water in the first place? if it's only to harvest the wave/tide energy, that doesn't really seem compelling enough to trade away the benefits of land. all very curious.

Thiel et al think there's a demand for R&D space near, but outside of, the USA in international waters where their work would not be subject to the US legal system. The Economist piece mentions a few of the major design & engineering issues that would would need to be overcome. Many of these posts raise other issues that would be moot because these seasteads would be commercial operations providing space for other businesses - ones that are, legally, not the same as any companies incorporated in the USA or any other nation.
Then there's the gratuitous political rants, but apparently some people will use any opportunity to vomit another 1.

and you don't get sea sick

Okay, your subject line answered your own question (i.e., "uninhabitable"). But beyond this, most "uninhabitable desert land" is also owned by the government, and is not for sale to anyone except wealthy mining companies with a big lobbying budget. Visit the Seasteading webiste (http://seasteading.org) and go through the FAQ section, which addresses all of these concerns.

Now, I'm NOT a Libertarian, but this is what the concept needs: a laboratory for Libertarians to run things THEIR way and see IF it works out...

Only problem: they would be all for regulation-free fishing, whaling, jelly-fishing, pretty much whatever. And I'm sorry, but there simply are NOT enough fish in the Ocean to satisfy these no-holds-barred folks.

Letting them take what they WILL want, will put an unsustainable load on those resources, which are over-strained as is.

Fishing would not be regulation-free in a libertarian society such as this, it would just be regulated in a different way -- based on property rights instead of government permission. Someone would own the sea life and that person would have rights to harvest (or not) that sea life.

This plan does not show how the logistics would work for the inhabitants. If the entire "island nation" consists of millionares then how do they plan to provide enough food and water for everyone? What would the population capacity be for such a group? Then there are the problems associated with weathering, wear and tear on the infrastructure. This sounds like a possible solution to lack of land area for the ever growing population of people, but it also sounds like "Water World" with the dysfunctions apparent in the movie.

Desalination can provide as much water as you want, you just need the power to run it. So, the problem becomes: How would they provide enough power for everyone?

Food could be imported, as is done in most cities around the world.

Weathering and wear and tear just requires lots of maintenance; smart design wouldn't hurt either.

Apprently the fall of the USSR was not a big enough sample.

Before anyone says it, China is the most successful implimentation of socialism with crony capitalism funding.

Are you suggesting sea-steading is being proposed by socialists? As something like a 1960's commune? I thought the author said they were mostly libertarians -- about as far from socialism as you can get!