How is boiled rice different from steamed?
It depends a great deal on the kind of rice you use. My father always steamed rice in a closed pot with a measured amount of water using American long grain rice. The ratio was one cup rice to two cups of water. 

When I got my own place I used the boiling method but chose Basmati rice, as is commonly used in india. This rice has a longer grain and holds its shape after cooking. I tried the boiling method with American long grain rice and found it also worked well. There is no need to measure the water as you cook by timer and taste the rice before draining. It's something similar to how you might cook pasta.

Contrary to what ElendilTheTall said in his answer, when boiling rice you do not have to make careful measurements of rice an water. You put in enough rice for how ever many people and an excess of water. Too much water. You cook the rice in an open pan, so you can see it. When the rice has cooked long enough, you pick out a few grains on your fork and taste them. If they are just soft enough, not too soft, then you quickly drain the water in a sieve or colander and serve. Timing is crucial.

Now, when I move to China, I found a very different kind on rice. It was shorter grained and required several washes before could be cooked. This rice didn't boil well. The unless really well washed, the rice powder in the water turns in into something reassembling wall paper paste. Instead the steaming method must be used. To steam you need to carefully measure the rice and water to get the correct ration. You put on the heat and cover. When the rice has boiled almost dry, you take it off the heat and serve.