The very famous Club Penguin is a "gaming" or a "virtual life" site for kids aged four to four teen.
On this site they are a part of a world covered in snow.
They join it as penguins and live a life of one too.
Each player or penguin has to play games and earn enough money to buy things and meet the needs of a penguin.
They get invited to parties and get free gifts there too.
They each have an igloo of their own and can decorate it the way they want to.
Members can even have a theme-igloo.
Each penguin player can keep a pet "Puffle".
Puffles are tiny, furry creatures.
These are available in the market in the pet shops.
Puffles are available in various shades like pink, purple, red, blue, green and black.
But, these shades are available only to the members of the Club Penguin who have the advantage of keeping up to 12 puffles.
The non-members can choose only between the colors red or blue and can keep only two at a time.
All the shades of the puffles basically define the various breeds they are available in.
So the six colors are basically the various types of puffles and they each differ in their temperament and nature like the pink ones are energetic and happy ones, the purple ones are good dancers and like to blow bubbles, the red ones are adventurous, the blue ones are the calmest of the lot, the green ones are very playful and the black ones have quite an attitude.
Yellow puffles are said to join this world too very soon.
It is a lot of fun to have a puffle as a pet and the more the merrier.
They each have a unique personality and so the master penguin reacts to each penguin differently.