Binary

There are 10 kinds of people.
1. those who understand binary
10. those who don't.

There are 100 kinds of people who might read this binary joke.
1. those who read it and understand it
10. those who read it and don't understand it
11. those who read it and will never understand it
100. those who don't read it

For those of you who don't get it, '10' in binary means 2, '100' in binary means 4.