If you are new to this game one of the first things you'll try to find out is usually how color codes work.
Many players use color codes although it can be misleading and annoying. Nevertheless they are useful for server admins and organized matches since they can help a lot to structure big groups of servers, or they can catch attention because of a color which is a interculturaö signal for a certain situation.
To use color codes, all you need to do is to type 0x and the html color code you need. Dark color codes have recently been banned out of most servers, but the most important ones are still available, since they can hardly be abused to spam and distract other players at the same time; at least if you compare them to the dark ones.
the following image shows most color codes you will happen to see during your tron career. http://www.taoti.com/images/colorchart.gif
Here are some examples of color codes.
0x000ddd = blue 0xff6633 = orange 0xffffff = white 0xffff7f = default chat color 0xff0000 = red 0xffff00 = yellow 0x00ff00 = green 0xff00ff = pink
Some players chat only while they use color codes. Instead of hitting the chat-key they have an instant chat for "0x(colorcode) \" which allows them to talk with this color. This can be very confusing, especially if the used color is white.
There is also an Elaborate color explanation