Why do Boxers Skip and what is a double dutch?

Ok I'm slightly overweight (6', 17st ,36old) and I 'm looking for something to keep fit.
My father used to box when he was a policeman in London in the swinging sixties and tought us to skip
when we were young.
After watching a programme with my children today called Jump Nation- a skipping competition I've decided to take up skipping.
But there are two questions to answer.
Why do Boxers skip? From a trawl of the web it seems that it improves stamina, fitness levels and helps with the footwork.


Here's how to skip like a boxer. This is Tommy Broadbent from Leeds,UK




And what is a Double Dutch?
We'll it's a technique that can be seen in this video of the Texas A&M Jump Rope Team




So I'm off to look for my skipping rope or even I might buy a new one.