Too late. I'm started.
It is a really hard concept for some folks to understand, BUT-
Flat black allows infrared radiation (heat) to pass through very easily. Silver or white reflect infrared (as you said), as do polished surfaces. That is why propane tanks are silver or white, to reflect external heat and keep them cooler.
Now, visualize this - there are two sides to a coat of paint, one you can see, the other side is against whatever is painted with the paint AND IS THE SAME COLOR. A coat of silver paint on a smoker will reflect infrared, both from the outside (from the sun for example) and from the INSIDE, from your fire - that heat is reflected back into the smoker. Therefore it helps retain that heat inside your smoker and helps you use less fuel. Black, on the other hand, allows infrared to readily pass through it. So the heat inside your smoker is passing right through to the atmosphere.
Joe Q. Smoker painted the very first smoker built black like his wood stove, and they have been black ever since. It was passed down from all those wood stoves that were black so they would radiate as much heat as possible. Wood stoves have fire in them and are black, smokers have fire in them and, therefore, should also be black, right? Wrong.
Go here and read about infrared theory -
http://www.x20.org/library/thermal/infrared.htm
Enjoy.
