Since it`s a bit misleading. Salty water boils slower since a higher temperature is needed.
Also if you boil pasta you should get the water to ~sea water saltieness
Edit: It seems I was quite wrong (about the saltieness not the boiling point). The upper tollarable limit seems to be aroud ~2 % salt while the sea has around 3.5 % salt.
Let me start by telling you one very important thing: Never, ever, ever make your pasta water as salty as the sea. That is the worst advice anyone can give. It is repulsively, inedibly salty. Frankly, 3% salt is also way too salty.
Sorry, but you are not adding seawater level salty water to your pasta. You might think you are, but you definitely are not. The water should be very salty, but seawater is very very very salty.
Something that always confused me, as the water seems to react with bubbles when I throw salt into it. My theory is that little amount of energy gets released when the ion grid structure is broken up, but still boiling point is higher for salted water. Could absolutely be bullshit... maybe someone can explain?
Edit: Thank you all guys for taking the time to explain!
It's likely nucleation. Basically, the water wants to boil, however it can quite get over the hump to produce a gas bubble. When you add salt, the surface acts as a nucleation point. Once the bubble forms, it grows rapidly, often splitting and forming more.
You see this effect at the other end too. Supercooled water will remain liquid, until something becomes available to crystallise around. When this happens, the whole lot will freeze in seconds.
More water vapor made when you throw in salt when it's actively boiling? Likely a physical reaction rather than a change to boiling point. The surface of the salt is rough, creating more surface area for the molecules to turn into their gaseous form.
Similar to mentos and diet coke, gases suspended in liquid can be released more efficiently with rough surfaces.