For the purpose of retained energy (say if you wanted to use that steam for heating) there is only so far you can go with the physics of the system but as a means of separation or for concentrating this is a very impressive achievement. Lets hope it is one of those developments that makes it out of the lab.

How long does it take for the salt and other impurities to clog the sponge when vaporizing sea water?

Is it easier to extract hydrogen from steam?

Are nanoparticles used in concentrated pv electricity generation?

Nothing is said about the temperature of this alleged steam. Evaporation is one thing -- that can happen at very low temperature -- but to make steam, it must be at least 100°C (at Std pressure). What we have here is useful technology with poor terminology.

It uses cheap, non-toxic materials, okay. How much does it cost to process it per kg or m^3?

@piperTom
If you read the article it says that the steam is created using light concentrated ten times higher than ordinary sunlight which is concentrated on, if the picture is anything to go by, a very small area...and the water is boiling!
So, I guess, it's "real" steam and not simply evaporation (which, incidentally, are two very different things)

This is a longshot here, but could floating balls or pads be made of this stuff to place in the glacial bays at the poles. If more of the sunlight is used to evaporate the sea water, less will be left to warm the bay water, countering the loss of ice on the water. It would also put more moisture in the air, creating more (light reflecting) snow.

How do you collect the steam without blocking the sunlight from hitting the surface????

bullrun, you're assuming that all of the sunlight is entering from one direction only. Think prisms and mirrors.