In terms of power production - all power is the same. It is then transmitted 
over High Voltage cables - usually above 10K Volts. The power is then 
stepped down before it reaches our homes.

U.S, Japanese and some other countries receive 110V in the form of 2 wires - 
1 Live and 1 Neutral (2 phase system)

Other countries receive 2 live and in some cases 2 live in addition to 1 
neutral to create this 220-240V.

Historically many countries originally used the 110V or 2 phase system.

Some may argue that the US is behind or has just managed to stay afloat with 
this old system longer.

The only advantage to receveing 110V is less injury to the nervous system in 
case of electric shock.

The downside is due to more current to compensate for the power you are more 
likely to get more burn (Yes skin burning) due to the 110V.

The disadvantage of 110V as compared to 220V is more losses due to 
resistence. Higher current needed to compensate for lower voltage creates 
more heat and
therefore more resistence in the system and thus the need for more power.

The US is at 120 volts, not 110 volts. It was increased sometime around the 
1950s.

The historic reason for 110 volts was due to the DC power systems created by 
Thomas Edison. I think he chose 110 volts because that is what his light 
bulb
worked on. Later on these systems were converted to AC so you didn't need a 
power plant on every corner but the voltage wasn't changed so existing 
lighting
didn't need to be replaced (they didn't care if they got AC or DC)

An interesting question is why the rest of the world did _not_ wind up using 
110 volts. How did 220/230/240V get started over there?

The US system theoretically could be made as good as (slightly better, 
actually) than the European system with no infrastructure change, except to 
houses
themselves. US houses get 240 volts at the panel. If wall outlets all were 
fed with 240V you'd have the lower current and higher power advantage of the
European system and it would be safer, since each "hot" would still be only 
120V from ground (not 240V) which keeps the reduced shock hazard advantage.
Of course it is still possible to touch the two hots.

Don't worry about what people think; they don't do it very often.

Steve, K8SP